如何证明sinA+sinB=2sin((A+B)/2)cos((A-B)/2)
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![如何证明sinA+sinB=2sin((A+B)/2)cos((A-B)/2)](/uploads/image/z/1583301-21-1.jpg?t=%E5%A6%82%E4%BD%95%E8%AF%81%E6%98%8EsinA%2BsinB%3D2sin%28%28A%2BB%29%2F2%29cos%28%28A-B%29%2F2%29)
如何证明sinA+sinB=2sin((A+B)/2)cos((A-B)/2)
如何证明sinA+sinB=2sin((A+B)/2)cos((A-B)/2)
如何证明sinA+sinB=2sin((A+B)/2)cos((A-B)/2)
sinA+sinB=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)/2]sin[(A-B)/2]+sin[(A+B)/2]cos[(A-B)/2]-cos[(A+B)/2]sin[(A-B)/2=2sin((A+B)/2)cos((A-B)/2)
就和差化积啊