=∫e^sinxsinxdsinx

=∫sinxde^sinx

=e^sinx*sinx-∫e^sinxdsinx

=e^sinx*sinx-e^sinx+C

(2) Two-sided derivation:

xf(x)= 1/√( 1-x？ )

Then: f (x) =1/kx (1+x 2)-2dx.

= k/2∫( 1+x^2)^-2d( 1+x^2)

=-k/2* 1/( 1+x^2)

=k/2-k/ 10

=2k/5

=32

k=80