化简2tan(-α).cos(7π-α)/sin(5π-α)

化简：[sin(π+α)*cos(π-α)*tan(π-α)]/[cos(π/2+α)*tan(3π/2-α)*tan( 化简cos(α-π)cot(5π-α)/tan(2π-α)sin(-2π-α) 化简：(sin²αtanα+cos²α/tanα+2sinαcosα)sinαcosα 求证:[sin^2(π+α)*cos(π/2-α)+tan(2π-α)*cos(-α)]/-sin^2(-α)+tan( 已知tanα=-1/2,求sin(α-7π)cos(α+5π). 化简{sin(π+α)^3cos(-α)cos(π+α)}/{tan(π+α)^3cos(-π-α)^2} 已知sin a=2cos a 计算⑴（sinα+2cosα)/(5cosα-sinα) ⑵tan(α+π/4) 化简sin³（﹣α）cos(2π+α）tan（2π-α)/sin(α-2π）cos(α-3π/2)-tan(π [sin(2π+α）·tan(-α)·cos(-α)]÷[sin(-α)·cos(2π+α）·tan(2π+α）化简 求证tan(2π-α)sin(-2π-α)cos(6π-α)/cos(α-π)sin(5π-α)=-tanα 化简(sinα)^2tanα+cosα+(cosα)^2*1/tanα+2sinαcosα 化简：tanα*(cosα-sinα)+[sinα(sinα+tanα)/1+cosα]