\int_{0}^{2 \pi m} exp(i t) sin(t) dt

sin(t) =1/2i*[exp(it)-exp(-it)]

=> exp(it)*sin(t)=1/2i*[exp(2it)-1]

=> int {exp(it)*sin(t)} = 1/2i*int {exp(2it)-1} = it/2-1/4*exp(2it)

kato slozish limits t1=0, t2=2*pi*m ne e 0