Question

Evaluate: $\int {\tan }^{2}xdx$

Answer 1

$I=\int {\tan }^{2}dx$

$(1+{\tan }^{2}x={\sec }^{2}x)$

$I=\int ({\sec }^{2}x-1)dx$

$I=\int {\sec }^{2}xdx-\int 1.dx$

$I=\tan x-x+c$.