What is the Integral of (tan(x))^4(tan(x))4?

1 Answer
Jan 13, 2017

tan^3x-tanx+x+Ctan3xtanx+x+C.

Explanation:

Let I=int(tanx)^4dx=inttan^4xdxI=(tanx)4dx=tan4xdx.

:. I=inttan^2xtan^2xdx

=inttan^2x(sec^2x-1)dx

=inttan^2xsec^2xdx-inttan^2xdx

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

=J-intsec^2xdx+int1dx

=J-tanx+x, where,

J=inttan^2xsec^2xdx

To find J," we subst. "y=tanx," so that, "dy=sec^2xdx.

:. J=inty^2dy=y^3/3=1/3tan^3x. Finally, we have,

I=1/3tan^3x-tanx+x+C.

Enjoy Maths.!