{"id":673,"date":"2025-07-14T20:54:58","date_gmt":"2025-07-14T20:54:58","guid":{"rendered":"https:\/\/content.one.lumenlearning.com\/precalculus\/?post_type=chapter&#038;p=673"},"modified":"2025-12-15T19:22:43","modified_gmt":"2025-12-15T19:22:43","slug":"module-1-introduction-to-functions-cheat-sheet","status":"publish","type":"chapter","link":"https:\/\/content.one.lumenlearning.com\/precalculus\/chapter\/module-1-introduction-to-functions-cheat-sheet\/","title":{"raw":"Introduction to Functions: Cheat Sheet","rendered":"Introduction to Functions: Cheat Sheet"},"content":{"raw":"<h2 class=\"text-text-100 mt-3 -mb-1 text-[1.125rem] font-bold\">Essential Concepts<\/h2>\r\n<h3 class=\"text-text-100 mt-2 -mb-1 text-base font-bold\">Functions and Function Notation<\/h3>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">A <strong>function<\/strong> is a special type of relation where each input (<strong>domain<\/strong> value) corresponds to exactly one output (<strong>range<\/strong> value).<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">The notation [latex]f(x)[\/latex] is read as \"f of x\" and represents the output value when x is the input. For example, if [latex]f(x) = x^2 + 1[\/latex], then [latex]f(3) = 3^2 + 1 = 10[\/latex].<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>Determining if a Relation is a Function<\/strong><\/p>\r\n\r\n<ul class=\"[li_&amp;]:mb-0 [li_&amp;]:mt-1.5 [li_&amp;]:gap-1.5 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-disc flex flex-col gap-2 pl-8 mb-3\">\r\n \t<li class=\"whitespace-normal break-words pl-2\"><strong>From ordered pairs or tables:<\/strong> Check that no x-value repeats with different y-values<\/li>\r\n \t<li class=\"whitespace-normal break-words pl-2\"><strong>From a graph:<\/strong> Use the vertical line test\u2014if any vertical line intersects the graph more than once, it's not a function<\/li>\r\n<\/ul>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>Evaluating Functions<\/strong><\/p>\r\n\r\n<ul class=\"[li_&amp;]:mb-0 [li_&amp;]:mt-1.5 [li_&amp;]:gap-1.5 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-disc flex flex-col gap-2 pl-8 mb-3\">\r\n \t<li class=\"whitespace-normal break-words pl-2\"><strong>Algebraically:<\/strong> Substitute the input value for the variable and simplify<\/li>\r\n \t<li class=\"whitespace-normal break-words pl-2\"><strong>From a table:<\/strong> Find the input value and read the corresponding output<\/li>\r\n \t<li class=\"whitespace-normal break-words pl-2\"><strong>From a graph:<\/strong> Locate the x-value and find the corresponding y-coordinate<\/li>\r\n<\/ul>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">A function is <strong>one-to-one<\/strong> if each output corresponds to exactly one input. Use the <strong>horizontal line test<\/strong>: if any horizontal line intersects the graph more than once, the function is not one-to-one.<\/p>\r\n\r\n<h3 class=\"text-text-100 mt-2 -mb-1 text-base font-bold\">Domain and Range<\/h3>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">The\u00a0<strong>domain\u00a0<\/strong>is the set of all possible input values (x-values) for a function<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">The <strong>range <\/strong>is the set of all possible output values (y-values) for a function<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>Finding Domain from an Equation<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">Exclude values that would cause:<\/p>\r\n\r\n<ol class=\"[li_&amp;]:mb-0 [li_&amp;]:mt-1.5 [li_&amp;]:gap-1.5 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-decimal flex flex-col gap-2 pl-8 mb-3\">\r\n \t<li class=\"whitespace-normal break-words pl-2\"><strong>Division by zero:<\/strong> Set denominators \u2260 0<\/li>\r\n \t<li class=\"whitespace-normal break-words pl-2\"><strong>Even roots of negatives:<\/strong> Set expressions under even roots \u2265 0<\/li>\r\n \t<li class=\"whitespace-normal break-words pl-2\"><strong>For functions with both:<\/strong> Combine all restrictions<\/li>\r\n<\/ol>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>Finding Domain and Range from a Graph<\/strong><\/p>\r\n\r\n<ul class=\"[li_&amp;]:mb-0 [li_&amp;]:mt-1.5 [li_&amp;]:gap-1.5 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-disc flex flex-col gap-2 pl-8 mb-3\">\r\n \t<li class=\"whitespace-normal break-words pl-2\"><strong>Domain:<\/strong> Read the x-values from left to right where the graph exists<\/li>\r\n \t<li class=\"whitespace-normal break-words pl-2\"><strong>Range:<\/strong> Read the y-values from bottom to top where the graph exists<\/li>\r\n<\/ul>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>Interval Notation Tips<\/strong><\/p>\r\n\r\n<ul class=\"[li_&amp;]:mb-0 [li_&amp;]:mt-1.5 [li_&amp;]:gap-1.5 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-disc flex flex-col gap-2 pl-8 mb-3\">\r\n \t<li class=\"whitespace-normal break-words pl-2\">Use [ ] for included endpoints (\u2264 or \u2265)<\/li>\r\n \t<li class=\"whitespace-normal break-words pl-2\">Use ( ) for excluded endpoints (&lt; or &gt;)<\/li>\r\n \t<li class=\"whitespace-normal break-words pl-2\">Always write from smaller to larger value<\/li>\r\n \t<li class=\"whitespace-normal break-words pl-2\">Use [latex]\\cup[\/latex] to combine separate intervals<\/li>\r\n<\/ul>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">A <strong>piecewise function<\/strong> uses different formulas for different parts of the domain. To evaluate:<\/p>\r\n\r\n<ol class=\"[li_&amp;]:mb-0 [li_&amp;]:mt-1.5 [li_&amp;]:gap-1.5 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-decimal flex flex-col gap-2 pl-8 mb-3\">\r\n \t<li class=\"whitespace-normal break-words pl-2\">Determine which interval your input falls in<\/li>\r\n \t<li class=\"whitespace-normal break-words pl-2\">Use the formula for that interval<\/li>\r\n \t<li class=\"whitespace-normal break-words pl-2\">Substitute and evaluate<\/li>\r\n<\/ol>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">To graph a piecewise function, graph each piece on its specified interval, using open circles for excluded endpoints and closed circles for included endpoints.<\/p>\r\n\r\n<h3 class=\"text-text-100 mt-2 -mb-1 text-base font-bold\">Rates of Change and Behaviors of Graphs<\/h3>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">The <strong>a<\/strong><strong>verage rate of change<\/strong> measures how quickly a function's output changes relative to its input over an interval:<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">[latex]\\text{Average Rate of Change} = \\dfrac{f(x_2) - f(x_1)}{x_2 - x_1} = \\dfrac{\\Delta y}{\\Delta x}[\/latex]<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">The units are \"output units per input unit\" (like miles per hour or dollars per year).<\/p>\r\n\r\n<ul class=\"[li_&amp;]:mb-0 [li_&amp;]:mt-1.5 [li_&amp;]:gap-1.5 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-disc flex flex-col gap-2 pl-8 mb-3\">\r\n \t<li class=\"whitespace-normal break-words pl-2\">If a function is\u00a0<strong>increasing<\/strong>, the values go up as you move left to right (positive rate of change)<\/li>\r\n \t<li class=\"whitespace-normal break-words pl-2\">If a function is <strong>decreasing<\/strong>, the values go down as you move left to right (negative rate of change)<\/li>\r\n \t<li class=\"whitespace-normal break-words pl-2\">If a function is\u00a0<strong>constant<\/strong>, then the values stay the same (zero rate of change)<\/li>\r\n<\/ul>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>Local and Absolute Extrema<\/strong><\/p>\r\n\r\n<ul class=\"[li_&amp;]:mb-0 [li_&amp;]:mt-1.5 [li_&amp;]:gap-1.5 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-disc flex flex-col gap-2 pl-8 mb-3\">\r\n \t<li class=\"whitespace-normal break-words pl-2\"><strong>Local maximum:<\/strong> A point higher than nearby points (like a hilltop)<\/li>\r\n \t<li class=\"whitespace-normal break-words pl-2\"><strong>Local minimum:<\/strong> A point lower than nearby points (like a valley)<\/li>\r\n \t<li class=\"whitespace-normal break-words pl-2\"><strong>Absolute maximum:<\/strong> The highest point on the entire graph<\/li>\r\n \t<li class=\"whitespace-normal break-words pl-2\"><strong>Absolute minimum:<\/strong> The lowest point on the entire graph<\/li>\r\n<\/ul>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">Note: When stating where extrema occur, give the x-value. When stating the extrema value, give the y-value (or [latex]f(x)[\/latex] value).<\/p>\r\n\r\n<h2 class=\"text-text-100 mt-3 -mb-1 text-[1.125rem] font-bold\">Key Equations<\/h2>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>Average Rate of Change:<\/strong> [latex]\\dfrac{f(x_2) - f(x_1)}{x_2 - x_1}[\/latex]<\/p>\r\n\r\n<h2 class=\"text-text-100 mt-3 -mb-1 text-[1.125rem] font-bold\">Glossary<\/h2>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>absolute maximum<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">the largest output value over the entire domain of a function<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>absolute minimum<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">the smallest output value over the entire domain of a function<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>average rate of change<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">the change in output divided by the change in input over a specified interval<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>decreasing function<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a function where output values decrease as input values increase<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>dependent variable<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">the output variable in a function, often represented by y or [latex]f(x)[\/latex]<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>domain<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">the set of all possible input values for a function<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>function<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a relation where each input corresponds to exactly one output<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>horizontal line test<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a test to determine if a function is one-to-one; if any horizontal line intersects the graph more than once, it's not one-to-one<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>increasing function<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a function where output values increase as input values increase<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>independent variable<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">the input variable in a function, often represented by x<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>input<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a value from the domain that is entered into a function<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>interval notation<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a way of writing sets of numbers using brackets and parentheses to show included and excluded endpoints<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>local maximum<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a point where the function value is greater than all nearby points<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>local minimum<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a point where the function value is less than all nearby points<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>one-to-one function<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a function where each output value corresponds to exactly one input value<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>output<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">the value produced when an input is entered into a function<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>piecewise function<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a function defined by different formulas over different parts of the domain<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>range<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">the set of all possible output values for a function<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>rate of change<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a measure of how one quantity changes relative to another<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>relation<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a relationship between two sets of numbers<\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>vertical line test<\/strong><\/p>\r\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a test to determine if a graph represents a function; if any vertical line intersects the graph more than once, it's not a function<\/p>","rendered":"<h2 class=\"text-text-100 mt-3 -mb-1 text-[1.125rem] font-bold\">Essential Concepts<\/h2>\n<h3 class=\"text-text-100 mt-2 -mb-1 text-base font-bold\">Functions and Function Notation<\/h3>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">A <strong>function<\/strong> is a special type of relation where each input (<strong>domain<\/strong> value) corresponds to exactly one output (<strong>range<\/strong> value).<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">The notation [latex]f(x)[\/latex] is read as &#8220;f of x&#8221; and represents the output value when x is the input. For example, if [latex]f(x) = x^2 + 1[\/latex], then [latex]f(3) = 3^2 + 1 = 10[\/latex].<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>Determining if a Relation is a Function<\/strong><\/p>\n<ul class=\"[li_&amp;]:mb-0 [li_&amp;]:mt-1.5 [li_&amp;]:gap-1.5 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-disc flex flex-col gap-2 pl-8 mb-3\">\n<li class=\"whitespace-normal break-words pl-2\"><strong>From ordered pairs or tables:<\/strong> Check that no x-value repeats with different y-values<\/li>\n<li class=\"whitespace-normal break-words pl-2\"><strong>From a graph:<\/strong> Use the vertical line test\u2014if any vertical line intersects the graph more than once, it&#8217;s not a function<\/li>\n<\/ul>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>Evaluating Functions<\/strong><\/p>\n<ul class=\"[li_&amp;]:mb-0 [li_&amp;]:mt-1.5 [li_&amp;]:gap-1.5 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-disc flex flex-col gap-2 pl-8 mb-3\">\n<li class=\"whitespace-normal break-words pl-2\"><strong>Algebraically:<\/strong> Substitute the input value for the variable and simplify<\/li>\n<li class=\"whitespace-normal break-words pl-2\"><strong>From a table:<\/strong> Find the input value and read the corresponding output<\/li>\n<li class=\"whitespace-normal break-words pl-2\"><strong>From a graph:<\/strong> Locate the x-value and find the corresponding y-coordinate<\/li>\n<\/ul>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">A function is <strong>one-to-one<\/strong> if each output corresponds to exactly one input. Use the <strong>horizontal line test<\/strong>: if any horizontal line intersects the graph more than once, the function is not one-to-one.<\/p>\n<h3 class=\"text-text-100 mt-2 -mb-1 text-base font-bold\">Domain and Range<\/h3>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">The\u00a0<strong>domain\u00a0<\/strong>is the set of all possible input values (x-values) for a function<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">The <strong>range <\/strong>is the set of all possible output values (y-values) for a function<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>Finding Domain from an Equation<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">Exclude values that would cause:<\/p>\n<ol class=\"[li_&amp;]:mb-0 [li_&amp;]:mt-1.5 [li_&amp;]:gap-1.5 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-decimal flex flex-col gap-2 pl-8 mb-3\">\n<li class=\"whitespace-normal break-words pl-2\"><strong>Division by zero:<\/strong> Set denominators \u2260 0<\/li>\n<li class=\"whitespace-normal break-words pl-2\"><strong>Even roots of negatives:<\/strong> Set expressions under even roots \u2265 0<\/li>\n<li class=\"whitespace-normal break-words pl-2\"><strong>For functions with both:<\/strong> Combine all restrictions<\/li>\n<\/ol>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>Finding Domain and Range from a Graph<\/strong><\/p>\n<ul class=\"[li_&amp;]:mb-0 [li_&amp;]:mt-1.5 [li_&amp;]:gap-1.5 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-disc flex flex-col gap-2 pl-8 mb-3\">\n<li class=\"whitespace-normal break-words pl-2\"><strong>Domain:<\/strong> Read the x-values from left to right where the graph exists<\/li>\n<li class=\"whitespace-normal break-words pl-2\"><strong>Range:<\/strong> Read the y-values from bottom to top where the graph exists<\/li>\n<\/ul>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>Interval Notation Tips<\/strong><\/p>\n<ul class=\"[li_&amp;]:mb-0 [li_&amp;]:mt-1.5 [li_&amp;]:gap-1.5 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-disc flex flex-col gap-2 pl-8 mb-3\">\n<li class=\"whitespace-normal break-words pl-2\">Use [ ] for included endpoints (\u2264 or \u2265)<\/li>\n<li class=\"whitespace-normal break-words pl-2\">Use ( ) for excluded endpoints (&lt; or &gt;)<\/li>\n<li class=\"whitespace-normal break-words pl-2\">Always write from smaller to larger value<\/li>\n<li class=\"whitespace-normal break-words pl-2\">Use [latex]\\cup[\/latex] to combine separate intervals<\/li>\n<\/ul>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">A <strong>piecewise function<\/strong> uses different formulas for different parts of the domain. To evaluate:<\/p>\n<ol class=\"[li_&amp;]:mb-0 [li_&amp;]:mt-1.5 [li_&amp;]:gap-1.5 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-decimal flex flex-col gap-2 pl-8 mb-3\">\n<li class=\"whitespace-normal break-words pl-2\">Determine which interval your input falls in<\/li>\n<li class=\"whitespace-normal break-words pl-2\">Use the formula for that interval<\/li>\n<li class=\"whitespace-normal break-words pl-2\">Substitute and evaluate<\/li>\n<\/ol>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">To graph a piecewise function, graph each piece on its specified interval, using open circles for excluded endpoints and closed circles for included endpoints.<\/p>\n<h3 class=\"text-text-100 mt-2 -mb-1 text-base font-bold\">Rates of Change and Behaviors of Graphs<\/h3>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">The <strong>a<\/strong><strong>verage rate of change<\/strong> measures how quickly a function&#8217;s output changes relative to its input over an interval:<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">[latex]\\text{Average Rate of Change} = \\dfrac{f(x_2) - f(x_1)}{x_2 - x_1} = \\dfrac{\\Delta y}{\\Delta x}[\/latex]<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">The units are &#8220;output units per input unit&#8221; (like miles per hour or dollars per year).<\/p>\n<ul class=\"[li_&amp;]:mb-0 [li_&amp;]:mt-1.5 [li_&amp;]:gap-1.5 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-disc flex flex-col gap-2 pl-8 mb-3\">\n<li class=\"whitespace-normal break-words pl-2\">If a function is\u00a0<strong>increasing<\/strong>, the values go up as you move left to right (positive rate of change)<\/li>\n<li class=\"whitespace-normal break-words pl-2\">If a function is <strong>decreasing<\/strong>, the values go down as you move left to right (negative rate of change)<\/li>\n<li class=\"whitespace-normal break-words pl-2\">If a function is\u00a0<strong>constant<\/strong>, then the values stay the same (zero rate of change)<\/li>\n<\/ul>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>Local and Absolute Extrema<\/strong><\/p>\n<ul class=\"[li_&amp;]:mb-0 [li_&amp;]:mt-1.5 [li_&amp;]:gap-1.5 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-disc flex flex-col gap-2 pl-8 mb-3\">\n<li class=\"whitespace-normal break-words pl-2\"><strong>Local maximum:<\/strong> A point higher than nearby points (like a hilltop)<\/li>\n<li class=\"whitespace-normal break-words pl-2\"><strong>Local minimum:<\/strong> A point lower than nearby points (like a valley)<\/li>\n<li class=\"whitespace-normal break-words pl-2\"><strong>Absolute maximum:<\/strong> The highest point on the entire graph<\/li>\n<li class=\"whitespace-normal break-words pl-2\"><strong>Absolute minimum:<\/strong> The lowest point on the entire graph<\/li>\n<\/ul>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\">Note: When stating where extrema occur, give the x-value. When stating the extrema value, give the y-value (or [latex]f(x)[\/latex] value).<\/p>\n<h2 class=\"text-text-100 mt-3 -mb-1 text-[1.125rem] font-bold\">Key Equations<\/h2>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>Average Rate of Change:<\/strong> [latex]\\dfrac{f(x_2) - f(x_1)}{x_2 - x_1}[\/latex]<\/p>\n<h2 class=\"text-text-100 mt-3 -mb-1 text-[1.125rem] font-bold\">Glossary<\/h2>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>absolute maximum<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">the largest output value over the entire domain of a function<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>absolute minimum<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">the smallest output value over the entire domain of a function<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>average rate of change<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">the change in output divided by the change in input over a specified interval<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>decreasing function<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a function where output values decrease as input values increase<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>dependent variable<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">the output variable in a function, often represented by y or [latex]f(x)[\/latex]<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>domain<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">the set of all possible input values for a function<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>function<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a relation where each input corresponds to exactly one output<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>horizontal line test<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a test to determine if a function is one-to-one; if any horizontal line intersects the graph more than once, it&#8217;s not one-to-one<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>increasing function<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a function where output values increase as input values increase<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>independent variable<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">the input variable in a function, often represented by x<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>input<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a value from the domain that is entered into a function<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>interval notation<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a way of writing sets of numbers using brackets and parentheses to show included and excluded endpoints<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>local maximum<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a point where the function value is greater than all nearby points<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>local minimum<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a point where the function value is less than all nearby points<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>one-to-one function<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a function where each output value corresponds to exactly one input value<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>output<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">the value produced when an input is entered into a function<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>piecewise function<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a function defined by different formulas over different parts of the domain<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>range<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">the set of all possible output values for a function<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>rate of change<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a measure of how one quantity changes relative to another<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>relation<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a relationship between two sets of numbers<\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"><strong>vertical line test<\/strong><\/p>\n<p class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\" style=\"padding-left: 40px;\">a test to determine if a graph represents a function; if any vertical line intersects the graph more than once, it&#8217;s not a function<\/p>\n","protected":false},"author":67,"menu_order":1,"template":"","meta":{"_candela_citation":"[]","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"part":36,"module-header":"cheat_sheet","content_attributions":[],"internal_book_links":[],"video_content":null,"cc_video_embed_content":{"cc_scripts":"","media_targets":[]},"try_it_collection":null,"_links":{"self":[{"href":"https:\/\/content.one.lumenlearning.com\/precalculus\/wp-json\/pressbooks\/v2\/chapters\/673"}],"collection":[{"href":"https:\/\/content.one.lumenlearning.com\/precalculus\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/content.one.lumenlearning.com\/precalculus\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/content.one.lumenlearning.com\/precalculus\/wp-json\/wp\/v2\/users\/67"}],"version-history":[{"count":6,"href":"https:\/\/content.one.lumenlearning.com\/precalculus\/wp-json\/pressbooks\/v2\/chapters\/673\/revisions"}],"predecessor-version":[{"id":5085,"href":"https:\/\/content.one.lumenlearning.com\/precalculus\/wp-json\/pressbooks\/v2\/chapters\/673\/revisions\/5085"}],"part":[{"href":"https:\/\/content.one.lumenlearning.com\/precalculus\/wp-json\/pressbooks\/v2\/parts\/36"}],"metadata":[{"href":"https:\/\/content.one.lumenlearning.com\/precalculus\/wp-json\/pressbooks\/v2\/chapters\/673\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/content.one.lumenlearning.com\/precalculus\/wp-json\/wp\/v2\/media?parent=673"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/content.one.lumenlearning.com\/precalculus\/wp-json\/pressbooks\/v2\/chapter-type?post=673"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/content.one.lumenlearning.com\/precalculus\/wp-json\/wp\/v2\/contributor?post=673"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/content.one.lumenlearning.com\/precalculus\/wp-json\/wp\/v2\/license?post=673"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}