lifan5748
幼苗
共回答了25个问题采纳率:88% 举报
原式=(1+2sin(a/2)*cos(a/2)+2cos方(a/2)-1)(sin(a/2)-cos(a/2))/根号2*cos(a/2)
=2cos(a/2)*(sin(a/2)+cos(a/2))(sin(a/2)-cos(a/2))/根号2*cos(a/2)
=根号2*(sin(a/2)+cos(a/2))(sin(a/2)-cos(a/2))
=-根号2*(cos方(a/2)-sin方(a/2))
=-根号2cosa
1年前
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