cos 3k 1 3π α

Ccotβ=tan(3/2π-β)tanα

sin^2(α+π)cos(π+α)cot(-α+2π)/tan(π-α)cos^3(-α-π)=(-sinα)^2*(-cosα)*cot(-α)/(-tanα)cos^3(-α+π)=(sinα)

[Sin(π+α)\tan(π+α)]×[cot(2π-α)\cos(π+α)]×[sec(2π-α)\csc(π-α)]=[(-sinα)\tanα]×[(-cotα)\(-cosα)]×[secα

tan(2π-α)sin(-2π-α)cos(6π-α)/cos(α-π)sin(5π-α)=(-tana)(-sina)cosa/(-cosa)sina=-tana希望对你有帮助~

f(α)=sin(π-α)cos(2π-α)tan(-α+π)/sin(π+α)tan(2π-α)=sinacosa(-tana)/(-sina)(-tana)=-(sinacosatana/sina

cos2(π/4-α)-sin2(π/4-α)=cos(π/2-2α）-sin(π/2-2α)=sin2α-cos2α=√2(√2/2sin2α-cos2α)=√2sin(2α-π/4)根据二倍角公式

sin(π/4-α)+cos(π/4+α)=sin(π/4-α)+cos[π/2-(π/4-α)]=sin(π/4-α)+sin(π/4-α)=2sin(π/4-α)

f(a)=-cosasina=-1/5,cosa=-2根号6/5,f(a)=2根号6/5直接代入f(a)=f(-7派/6）=-根号3/2

[sin(π+α)*cos(π-α)*tan(π-α)]/[cos(π/2+α)*tan(3π/2-α)*tan(α-3π)]=[(-sinα)*(-cosα)*(-tgα)]/[(-sinα)*ct

-cosα对不对sin(π—α)=sinα,cos(2π—α)=cosα,tan（-α+3/2π)=ctgα,上面就是(cosα)^2;cot(-α-π）=-ctgα,sin(-π-α)=sinα,然

f(α)=[sin(π-α)cos(α-π)tan(-α+π)]/[tan(π+α)cos(3/2π+α)]=sinα(-cosα)(-tanα)/(tanαsinα)=cosα再问：cos(3/2π

f(α)=[sin(π-α）cos(2π-α）tan(-α+π）]/[-tan(-α-π）sin（-π-α）]=[sinαcosα(-tanα)]/{tanα[-sin(π+α)}=-sinαcosα

原式=(-sin³α)cosα(-cosα)/(tan³α)cos²α=sin³α/tan³α=sin³α/(sin³α/cos&

Σ'αγαπ=我爱你（这是希腊文.）

f(α)=(sinα*cosα*-tanα)/tan(π+α)*sin(π-α)=(-sinα*cosα*tanα)/tanα*sinα=-cosαcos(α-3π/2)=cos(α-3π/2+2π)

sin(π+α)比上cos(π+α)=tan(π+α)(利用同角关系式)=tanα（利用诱导公式）

cos(α-π)cot(5π-α)/tan(2π-α)sin(-2π-α)=-sinα*(-tanα)/(-tanα)sinα=-(sinα)^2

cos(-π-α)=-cos(-α)=-cosα

=cosα*sinα/（-cosα）+sinα*（-sinα）/-sinα=-sinα+sinα=0第二题继续啊,先占座（2）sin²40°+sin²50°=sin²40

tan(3/2π-α)=cotα；cot(-α-π)=-cot(π+α)=-cotα.