9.3.1.5 Indefinite integrals

Problem: Find indefinite integrals. Check the results by differentiation. 1) \( \int \frac{\tan x}{\cos ^{2} x} \), 2) \( \int \ln 3 x d x \), 3) \( \int \frac{x-8}{x(x-2)^{2}} d x \).