sin(20°+α)/cos(70°-α)-tan(50°+α)tan(40°-α)=
tan(90°-α)等于多少 化简就行了 用sin/cos =tan 的关系
化简cos^2(-α)-[tan(360°+α)/sin(-α)]
化简,cos²(-α)-tan(360°+α)/sin(-α)
为什么 3.sin(-α)=-sina cos(-a)=cosα 4*.tan(180°+α)=tanα tan(-α)
已知tanα=3/4,α是锐角,求tan(90°-α),sinα,cosα的值,
设cos(180°+α)=1/3 且 sinα>α 求sin(180°+α)-tanα/cos(180°-α)+tan(
.[1/cos(-α)+cos(180°+ α )]/[1/sin(540°-α)+sin(360°-α)]=tan^3
sin(540°+α)cos(360°-α)/sin(450°+α)tan(900°-α)
sin(α-180°)+tan(315-β)/tan(β+45°)+cos(α+270°)的值为
求证cos(720°+α)(2/cosα+tanα)(1/cosα-2tanα)=2cosα-3tanα
1-sinαcos/cos平方α-sin平方=1-tanα/1+tanα
证明恒等式tanαsinα/tanα-sinα=1+cosα/sinα