What is the integral of 1/((a^2+x^2)) ?

The integral of 1/((a^2+x^2)) is 1/a arctan(x/a)+C

integral of 1/((a^2+x^2))

integral

\frac{1}{( a ^{2} + x ^{2} )}

\frac{1}{a} arctan (\frac{x}{a}) + C

Solution steps

\int \frac{1}{a ^{2} + x ^{2}} d x

Apply Integral Substitution

= \int \frac{1}{a ( u ^{2} + 1 )} d u

Take the constant out:

\int a \cdot f (x) d x = a \cdot \int f (x) d x

= \frac{1}{a} \cdot \int \frac{1}{u ^{2} + 1} d u

Use the common integral:

\int \frac{1}{u ^{2} + 1} d u = arctan (u)

= \frac{1}{a} arctan (u)

Substitute back

u = \frac{x}{a}

= \frac{1}{a} arctan (\frac{x}{a})

Add a constant to the solution

= \frac{1}{a} arctan (\frac{x}{a}) + C

in t e g r a l \frac{x}{( 1 - x ^{2} )}

in t e g r a l \frac{e ^{x}}{x ^{2}}

in t e g r a l \frac{x}{81 x ^{4} - 1}

in t e g r a l \frac{1}{( 4 - x ^{2} )}

in t e g r a l \frac{1}{( x ^{2} + x + 1 )}

What is the integral of 1/((a^2+x^2)) ?
The integral of 1/((a^2+x^2)) is 1/a arctan(x/a)+C