How do you integrate (tanx)^8(tanx)8?

1 Answer
Apr 13, 2017

tan^7x/7-tan^5x/5+tan^3x/3-tanx+x+C.tan7x7tan5x5+tan3x3tanx+x+C.

Explanation:

Let, I=inttan^8xdx=inttan^6x(sec^2x-1)d,I=tan8xdx=tan6x(sec2x1)d,

=int(tanx)^6d(tanx)-inttan^4x(sec^2x-1)dx,=(tanx)6d(tanx)tan4x(sec2x1)dx,

=tan^7x/7-int(tanx)^4d(tanx)+inttan^2x(sec^2x-1)dx,=tan7x7(tanx)4d(tanx)+tan2x(sec2x1)dx,

=tan^7x/7-tan^5x/5+int(tanx)^2d(tanx)-inttan^2xdx,=tan7x7tan5x5+(tanx)2d(tanx)tan2xdx,

=tan^7x/7-tan^5x/5+tan^3x/3-int(sec^2x-1)dx.=tan7x7tan5x5+tan3x3(sec2x1)dx.

:. I=tan^7x/7-tan^5x/5+tan^3x/3-tanx+x+C.

Enjoy Maths.!