Integration is the opposite of differentiation. Now to integrate a given function, we look for the derivative of the given function. For instance how to integrate sec^2(x)/tan(x).

\text{find the integral of }\space\int\frac{ \text{sec}^2x}{\text{tan}x}dx\\ Answer: \text{To integrate a }\space\\\int\frac{\text{f(x)}}{f'(x)}dx\\ \text{since the numerator is a derivative }\\\text{of the denominator}\space, \text{we take the}\\\text{ ln of the denominator}\\ Hence: \text{integral of }\space \int\frac{sec^2(x)}{tan(x)}dx\\=ln\space\text{tan(x)}+c, \\\text{where c is a constant}