sin 两次方x除以2乘以cos两次方x除以2等于什么啊
问题描述：
sin 两次方x除以2乘以cos两次方x除以2等于什么啊
[sin^2(x/2)]*[cos^2(x/2)]
答
是不是[sin(x/2)]^2*[cos(x/2)]^2?
如果是则
[sin(x/2)]^2*[cos(x/2)]^2
=[sin(x/2)cos(x/2)]^2
=[(1/2)*sin(x/2)cos(x/2)]^2
=(1/4)[sin(2*x/2)}^2
=(1/4)(sinx)^2