已知sin(α+β)sin(α-β)=m,求cos^2α-cos^2βsin(α+β)sin(α-β)=m=sin^2α-sin^2βcos^2α-cos^2β=(1-sin^2α)-(1-sin^2β)=sin^2α-sin^2β=m 感谢网友批评指正 弄错了一个符号嘿嘿 回答了几十个问题 眼花了~...