已知角α终边上一点P(-4,3),求cos(5π/2+α)sin(-π+2α)/cos(11π/2-α)sin(9π/2+α)的值.前面是5π/2!好多题是π/2.

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已知角α终边上一点P(-4,3),求cos(5π/2+α)sin(-π+2α)/cos(11π/2-α)sin(9π/2+α)的值.前面是5π/2!好多题是π/2.已知角α终边上一点P(-4,3),求

已知角α终边上一点P(-4,3),求cos(5π/2+α)sin(-π+2α)/cos(11π/2-α)sin(9π/2+α)的值.前面是5π/2!好多题是π/2.
已知角α终边上一点P(-4,3),求cos(5π/2+α)sin(-π+2α)/cos(11π/2-α)sin(9π/2+α)的值.
前面是5π/2!好多题是π/2.

已知角α终边上一点P(-4,3),求cos(5π/2+α)sin(-π+2α)/cos(11π/2-α)sin(9π/2+α)的值.前面是5π/2!好多题是π/2.
角α终边上一点P(-4,3),则:sinα=3/5,cosα=-4/5
原式=sinαsin2α/(-sinαcosα)
=-2sinα
=-6/5