cos*π/12—sin*π/12

cos*π/12—sin*π/12 （sinπ/24)(cosπ/24)(cosπ/12) （sinπ/24)(cosπ/24)(cosπ/12) sinπ/12*cosπ/12=? 求值：sin(π/12)+cos(π/12) sin(π/12)-cos(π/12)= cosπ／12乘以sinπ／12 计算cosπ/12*sinπ/12 （cosπ/12-sinπ/12)*(COSπ/12+sinπ/12)等于 (cosπ/12 -sinπ/12)(cosπ/12 +sinπ/12)等于 （cosπ/12-sinπ/12)(cosπ/12+sinπ/12)的值为 （cosπ/12 -sinπ/12）（cosπ/12 +sinπ/12）= (sinπ/12+cosπ/12)(sinπ/12-cosπ/12)= 已知α=7/12π,那么cosα√（1-sinα）/(1+sinα)+sinα√（1-cosα）/(1-cosα)= cos^2π/12-sin^2π/12等于 sin(π/12)cos(π/12)的值 求sin π/12-(根号3)cos π/12 cosπ/12+(根号3)×sinπ/12的值