Evaluate the integral of tan^2(x) dx.

The integral of tan^2(x) dx is equal to tan(x) - x + C, where C is the constant of integration.

To evaluate the integral of tan^2(x) dx, we can use the identity 1 + tan^2(x) = sec^2(x). Rearranging this identity, we get tan^2(x) = sec^2(x) - 1. Substituting this into the integral, we get:

∫tan^2(x) dx = ∫(sec^2(x) - 1) dx

Using the integral of sec^2(x), which is tan(x), we can evaluate the integral as follows:

∫tan^2(x) dx = ∫(sec^2(x) - 1) dx
= tan(x) - x + C

Therefore, the integral of tan^2(x) dx is equal to tan(x) - x + C, where C is the constant of integration.