Question

sin^2(3П/2+a)/ctg(a-2П) +sin^2 (-a) /ctg^2 (a-3П/2)

Answer 1

$frac{Sin ^{2}( frac{3 pi }{2}- alpha ) }{ctg( alpha -2 pi )} + frac{Sin ^{2} (- alpha )}{ctg ^{2}( alpha - frac{3 pi }{2}) } = frac{Cos ^{2} alpha }{ctg alpha } + frac{Sin ^{2} alpha }{tg ^{2} alpha }=Sin alpha Cos alpha +Sin alpha Cos alpha =$$2Sin alpha Cos alpha$