化简:2sin^2(19/4π)+tan^2(37/4π)*cot(-9/4π)
化简sin(θ-5π)•cot(π2-θ)•cos(8π-θ)tan(3π-θ)•tan(θ-32π)•sin(-θ-4
化简 cot(a+4π)cos(a+π)[sin(a+3π)]^2/tan(π+a)[cos(-π-a)]^2
1)求证cotαcosα/cotα-cosα=tan(α/2+π/4)
已知sin(π/4+α)*sin(π/4-α)=1/4,α∈(π/4,π/2),求2sin^α+tanα-cotα-1的
已知tan(π/4+α)=-3,求[2(Sinα)的平方+3SinαCosα]/(Cotα-SinαCosα)的值.
化简:sin(a-π)cot(a-2π)/cos(a-π)tan(a-2π)
化简cos(α-π)cot(5π-α)/tan(2π-α)sin(-2π-α)
化简sin(3π+a)tan(a-π)cot(π+a)/tan(2π-a)cos(π-a)
化简sin(2π-a)tan(π+a)cot(-a-π)\cos(π-a)tan(3π-a)
若a=[cot(4π+a)cos(a+π)sin^2(3π+a)]/[tan(π+a)cos^3(-a-π)]则a^2+
[cot(θ+4π)·cos(θ+π)·sin^2(θ+3π)]/[tan(π+θ)·cos^3(-π-θ)]
已知tan α+cot α=5/2,α∈(π/4,π/2),求cos 2α和sin(2α+π/4)的值