Question

$3a*cos^{2}2 pi*sin frac{ pi }{2} -b*cos pi *ctg frac{3 pi }{2}$

Answer 1

$3a*cos^2(2pi)*sin(frac{pi}2)-2b*cos(pi)*ctg(frac{3pi}2)\cos(2pi)=1\sin(frac{pi}2)=1\cos(pi)=-1\ctg(frac{3pi}2)=0\3a*(1)^2*1-2b*(-1)*0=3a$

Ответ: 3a.