How do you find the antiderivative of sinx/(1-cosx)sinx1−cosx?
1 Answer
Jul 5, 2016
You can simply do a u-substitution.
Let:
u = -cosxu=−cosx
du = sinxdxdu=sinxdx
Therefore, the antiderivative/integral is:
color(blue)(int sinx/(1-cosx)dx)∫sinx1−cosxdx
= int 1/(1+u)du=∫11+udu
= ln|1+u|=ln|1+u|
= color(blue)(ln|1-cosx| + C)=ln|1−cosx|+C
We know this works because:
color(green)(d/(dx)[ln|1-cosx| + C])ddx[ln|1−cosx|+C]
= 1/(1-cosx)*sinx + 0=11−cosx⋅sinx+0
(chain rule)
= color(green)(sinx/(1-cosx))=sinx1−cosx