1/1-cosA等于多少
问题描述:
1/1-cosA等于多少
答
cosA=cos(A/2+A/2)=cos(A/2)-sin(A/2)=2cos(A/2)-1 1-cosA=2-2cos(A/2) 1/(1-cosA)=1/2 ×1/sin(A/2) (sinA+cosA=1)
1/1-cosA等于多少
cosA=cos(A/2+A/2)=cos(A/2)-sin(A/2)=2cos(A/2)-1 1-cosA=2-2cos(A/2) 1/(1-cosA)=1/2 ×1/sin(A/2) (sinA+cosA=1)