Integrals Resulting in Inverse Trigonometric Functions: Learn It 2
Integrals Resulting in Other Inverse Trigonometric Functions
There are six inverse trigonometric functions. However, only three integration formulas are noted in the rule on integration formulas resulting in inverse trigonometric functions because the remaining three are negative versions of the ones we use. The only difference is whether the integrand is positive or negative.
Rather than memorizing three more formulas, if the integrand is negative, simply factor out [latex]−1[/latex] and evaluate the integral using one of the formulas already provided.
Find an antiderivative of [latex]\displaystyle\int \frac{1}{1+4{x}^{2}}dx.[/latex]
Comparing this problem with the formulas stated in the rule on integration formulas resulting in inverse trigonometric functions, the integrand looks similar to the formula for [latex]{ \tan }^{-1}u+C.[/latex]
So we use substitution, letting [latex]u=2x,[/latex] then [latex]du=2dx[/latex] and [latex]\frac{1}{2}du=dx.[/latex]