Question

вычислите ctgx, если tg(x/2)=5/3

Answer 1

tgx/2=5/3
ctgx/2=1:tgx/2=1:5/3=3/5
ctgx=(ctg²x/2-1)/2ctgx/2=(9/25-1):(2*3/5)=-16/25*5/6=-8/15