How do you find int 1-tanx^2dx1tanx2dx?

1 Answer
Dec 3, 2015

int(1-tan^2x)dx = 2x- tan x +C(1tan2x)dx=2xtanx+C

Explanation:

We can start of by doing the following

int 1-tan^2x dx = int 1 dx - int tan^2x dx1tan2xdx=1dxtan2xdx

Then integrate the first integral

= x- int(sec^2x -1)dx=x(sec2x1)dx

Rewrite using trigonometric identity

  • color(red)(tan^2 x = sec^2x - 1)tan2x=sec2x1

= x- [int(sec^2x) dx -int1dx]=x[(sec2x)dx1dx]
color(red)(int (sec^2x dx= tan x + C)(sec2xdx=tanx+C)

= x- [ tan x -x] +C=x[tanxx]+C

= 2x- tan x +C=2xtanx+C