Which of the following equals

MATHEMATICS · Single correct · AP · Calculus AB · Integration and Accumulation of Change · Integration and Accumulation of Change

Problem

\displaystyle \int \frac{dx}{x^{2}+a^{2}}\;?

(a)

\ln|x^{2}+a^{2}|+C

(b)

\dfrac{1}{a}\arctan\left(\dfrac{a}{x}\right)+C

(c)

\dfrac{1}{a}\arctan\left(\dfrac{x}{a}\right)+C

(d)

\dfrac12\,\arctan\left(\dfrac{x}{a}\right)+C