Wize University Calculus 1 Textbook > Integrals

Antiderivatives of Inverse Trig Functions

0:00 / 0:00

Antiderivatives (Indefinite Integrals) of Inverse Trig Functions

Let a>0a>0. Then we have the following indefinite integral rules:

1a2x2dx=arcsin(xa)+C\displaystyle \boxed{\int\frac{1}{\sqrt{a^2-x^2}}dx=\arcsin \left(\frac{x}{a}\right)+C}


1a2+x2dx=1aarctan(xa)+C\displaystyle \boxed{\int\frac{1}{{a^2+x^2}}dx=\frac{1}{a}\arctan \left(\frac{x}{a}\right)+C}

1xx2a2dx=1aarcsec(xa)+C\displaystyle \boxed{\int\frac{1}{x\sqrt{x^2-a^2}}dx=\frac{1}{a}\arcsec \left(\frac{|x|}{a}\right)+C}

Watch Out!
Different sources will state slightly different versions of the integral involving arcsecx\arcsec x.

0:00 / 0:00

Example: Inverse Trig Indefinite Integrals

Evaluate the following indefinite integral

2x2+9dx\displaystyle \int\frac{2}{\sqrt{-x^2+9}}dx

1a2x2dx=arcsin(xa)+C\displaystyle \int\frac{1}{\sqrt{a^2-x^2}}dx=\arcsin \left(\frac{x}{a}\right)+C

2x2+9dx=2×19x2dx\displaystyle \int\frac{2}{\sqrt{-x^2+9}}dx=\displaystyle \int2\times\frac{1}{\sqrt{9-x^2}}dx

=2×132x2dx=\displaystyle \int2\times\frac{1}{\sqrt{3^2-x^2}}dx

=2arcsin(x3)+C\displaystyle =\boxed{2\arcsin \left( \frac{x}{3}\right)+C}

Evaluate the following indefinite integral

14+2x2dx\displaystyle \int\frac{1}{4+2x^2}dx
Extra Practice