已知sinα是方程5x^2-7x-6=0的根,且α为第三象限角 求

问题描述:

已知sinα是方程5x^2-7x-6=0的根,且α为第三象限角 求
sin(-α-3/2*π)*cos(3/2*π-α)*tan^2(π-α)÷cos(π/2-α)*sin(π/2+α)的值

5x^2-7x-6=0(5x+3)(x-2)=0x=-3/5或x=2(舍去)sinα=-3/5α为第三象限角 cosα=-4/5sin(-α-3/2*π)*cos(3/2*π-α)*tan^2(π-α)÷cos(π/2-α)*sin(π/2+α)=-cosαsinα*tan²α÷sinα*(-cosα...