cos（9π/4)+tan（-7π/6）+sin（21π）=

cos（9π/4)+tan（-7π/6）+sin（21π）= 化简sin(9π+α）tan（3/2π+α）/cos(-4π-α）tan（15π+α）tan(7/2π-α） Sinπ/3Tanπ/3+tanπ/6COSπ/6－Tanπ/4COSπ/2 cos11π/4+tan（-7π/6）+sin（-π）+cos（-5π/6） sin ² 9π/2+cos²（ -13π/4）-tan²7π/3 计算（1）cosπ/3-tanπ/4+3/4tan²π/6-sinπ/6+cos²π/6cosπ/3-tanπ/4+3/4tan²π/6-sinπ/6+cos²π/6[tan(-150°)cos（-210°）cos420°]/cot(-600°)sin（-1050°）cos25/6π+cos25/3π+tan(-25/4π)5sinπ/2+2cos0-3sin3/2π+10cosπt 计算cosπ/3-tanπ/4+3/4tan²π/6-sinπ/6+cos²π/6cosπ/3-tanπ/4+3/4tan²π/6-sinπ/6+cos²π/6[tan(-150°)cos（-210°）cos420°]/cot(-600°)sin（-1050°）cos25/6π+cos25/3π+tan(-25/4π)5sinπ/2+2cos0-3sin3/2π+10cosπtan10°t sin29π/6+cos(-29π/3)+tan(-25/4) cos(-π/4)乘tan(-5π/6)=? tan(-2010°)+cos(-79π/6) cosπ|3-tanπ|4+3|4tan²π|6+cos²π|6-sinπ|4 cosπ/3+tanπ/4+3tan²π/6+sinπ/2+cosπ+sin3π/2等于?. 求证：1/cosα-tanα=1/tan（π/4+α/2） 已知(1+tanα)(1+tanβ)=4cos（π/3）0 化简（-11/6 π)+cos(12/5 π)tan（4π）-1/(cos(13π/3)) 已知tan=2,求cos^4(π/3+α）-cos^4（α-π/6）的值 cos（-7 π /4） 还有tan （19 π /3） 求值 求值:2cosπ/2-tanπ/4+3/4tan²π/6-sinπ/6+cos²π/6+sin3π/2 -1/4cosπ