计算cos(-585°)/sin495°+sin(-57..

①sin(-π/4)②sin13/6π③cos5/4π④tan(-7/4π)⑤-cos(-300°)⑥sin495° sin,cos怎么计算 计算机计算sin cos 计算[3/(sin^2)20°-[1/(cos^2)20°]+64(sin^2)20° 计算器计算sin tan cos 计算：sin(-1200°）·cos1230°+cos（-1020°）sin(-1050°）+tan1305° 计算：sin²30°+cos²45°+根号2sin60°×tan45° 数学三角函数计算sin(a)*cos(a)=1/8,45°＜a＜90°,求cos(a)-sin(a)的值 已知tanα=2,计算:[sin(90°+α)-cos(180°-α)]/[sin(90°-α)-sin(180°-α) 计算cosπ/12*sinπ/12 直角三角形sin cos tan cot 计算 数学 tan cot sin cos 的计算