let f(x)=Σ_(n=1) ^∞ (1/n) cos^n (x)sin(nx)
1)prove the convergence of this serie
2)prove that f is C^2 on R −{kπ,k∈Z}and
calculate f^′ (x)
3) give a exprrssion of f.
1) find the value of ∫_0 ^1 ln(1−x^3 )dx then
find the value of ∫_0 ^1 ln(1+x+x^2 )dx
2)find the value of ∫_0 ^1 ln(1+x^3 )dx then
calculate ∫_0 ^1 ln(1−x +x^2 )dx