赞 leemansize 幼苗
共回答了25个问题采纳率：96% 举报
4cos(A/2)cos(B/2)cos(C/2)=4cos(A/2)cos(B/2)cos(pi/2-A/2-B/2)=4cos(A/2)cos(B/2)sin(A/2+B/2)=4cos(A/2)cos(B/2)(sin(A/2)cos(B/2)+sin(B/2)cos(A/2))=2sinAcos(B/2)^2+2sinBcos(A/2)^2==>4cos(A/2)cos(B/2)cos(C...
1年前
9
可能相似的问题
你能帮帮他们吗