化简sin(2π-α)*tan(π+α)*cot(-α-π)/cos(π-α)*tan(3π-α)(急)
化简sin(2π-α)*tan(π+α)*cot(-α-π)/cos(π-α)*tan(3π-α)(急)
化简sinαcosα(tanα+cotα)
化简tanα(cosα-sinα)+sinα+tanαcotα+cscα
【sin(α+2kπ)+cos(π/2+α)+tan(3π-α)】/【sin(α-π)+cos(α-π/2)+cot(π
化简 f(α)=sin(π—α) cos(2π—α)tan(-α+3/2π)/cot(-α-π)sin(-π-α)
化简sin(3π+a)tan(a-π)cot(π+a)/tan(2π-a)cos(π-a)
证明下列恒等式(1)1/tanα+cotα=sinαcosα(2)tanα+cotα-2/tanα+cotα+2
化简sin³(﹣α)cos(2π+α)tan(2π-α)/sin(α-2π)cos(α-3π/2)-tan(π
化简cos(α-π)cot(5π-α)/tan(2π-α)sin(-2π-α)
化简sin^2(α+π)cos(π+α)cot(-α+2π)/tan(π-α)cos^3(-α-π)
已知tan α+cot α=5/2,α∈(π/4,π/2),求cos 2α和sin(2α+π/4)的值
[sin(2π+α)·tan(-α)·cos(-α)]÷[sin(-α)·cos(2π+α)·tan(2π+α)化简