Question

sinAsinB等于多少？

Answer 1

sinA等于sinB加那个啥再乘那个某某某！再加减乘除跟号几的同一个数！然后你就上瘾了！继续吧！♀

Answer 2

sinAsinB=sin[(A+B)/2+(A-B)/2]*sin[(A+B)/2-(A-B)/2]
=[sin(A+B)/2*cos(A-B)/2+cos(A+B)/2sin(A-B)/2]*[sin(A+B)/2*cos(A-B)/2-cos(A+B)/2sin(A-B)/2]
=[sin(A+B)/2*cos(A-B)/2]^2-[cos(A+B)/2sin(A-B)/2]^2
=[1-cos^2(A+B)/2]cos^2(A-B)/2-cos^2(A+B)/2sin^2(A-B)/2
=cos^2(A-B)/2-cos^2(A+B)/2[sin^2(A-B)/2+cos^2(A-B)/2]
=cos^2(A-B)/2-cos^2(A+B)/2
=1/2[1+cos(A-B)]-1/2[1+cos(A+B)]
=1/2[cos(A-B)-cos(A+B)]

Answer 3

sinAsinB=－(1/2)[cos(A＋B)/2－cos(A－B)/2]

Answer 4

到数学用表查一下不知道了。