化简cos(a-B)cos(a-y)-sin(a-B)sin(y-a)

化简cos(a-B)cos(a-y)-sin(a-B)sin(y-a) sin(a+B)cos(y-B)-cos(B+a)sin(B-y) 化简 sin（a+B)sin(B-y)-cos(a-B)cos(y-B) 化简 怎样把cos(x)cos(y)转换成cos(a)+cos(b)的形式 化简COS(a+B)COS(a-B)+sin平方B 化简cos(a+b)cos(a-b)+sin^2b matlab怎么绘制函数s=a*cos(x)+b*cos(y)的图像,a,b是已知量 化简：2cos(A+B)cosB-cos(2A+B) y=cos(a+b)怎么求导 COS(a-B)公式 证明cos(A+B) 化简 cos(a+b)cosa+sin(a+b)sina=_______ cos(31°-a)cos(29°+a)-cos(59°+a)cos(61°-a) 若A+B=120°,则函数Y=cos^2A+cos^2B的最大值是 Y=cos^2A+cos^2B =2COS(A+B)COS(A-B)+1 这步怎么得到? cos a-cos b 公式是什么? 化简sin^2acos^b-cos^2asin^2b+cos^a-cos^2b cos(a+b)+cos(a-b)/sin(a+b)+sin(a-b)化简 化简 cos(a-b)cos(a+b)+sin(a-b)sin(a+b). cos(a-b)cos(a+b)+sin(a-b)sin(a+b)化简,