Question

三角函数化简化简:-sin^2(π+a)·sin(π-a)-tan(2π-a)·cos(-a)/csc^2(-a)+ta

Answer 1

原式=-sin^2(a)*sin(a)-(-tan(a))*cos(a)/csc^2(a)+tan(a)*(-cot(a))

=-sin^3(a)+tan(a)*cos(a)*sin^2(a)-1

=-sin^3(a)+sin^3(a)-1

=-1