Question

What is the value of \(\int \frac{1}{x^2 + 1} \, dx\)?

• A. \(\ln|x + 1| + C\)
• B. \(\tan^{-1}x + C\)
• C. \(\ln|x - 1| + C\)
• D. \(\tan^{-1}(x^2) + C\)

Hint:

The integral \(\int \frac{1}{x^2 + a^2} \, dx = \frac{1}{a} \tan^{-1}\left(\frac{x}{a}\right) + C\) is a key formula in calculus.