coa^2a/2+sin^2a/2=1
-coa^2a/2+sin^2a/2=1/2
sin^2a/2=3/4
cos^2a/2=1/4
cosa=-1/2
sina=根号3/2
a/sina=b+c/sinb+sinc=2r=8根号3
sinb=sin(60-c)
sinb+sinc=根号3/2cosc+1/2sinc
b+c=8根号3(根号3/2cosc+1/2sinc)=8根号3sin(c+60) c属于(0,60)
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coa^2a/2+sin^2a/2=1
-coa^2a/2+sin^2a/2=1/2
sin^2a/2=3/4
cos^2a/2=1/4
cosa=-1/2
sina=根号3/2
a/sina=b+c/sinb+sinc=2r=8根号3
sinb=sin(60-c)
sinb+sinc=根号3/2cosc+1/2sinc
b+c=8根号3(根号3/2cosc+1/2sinc)=8根号3sin(c+60) c属于(0,60)
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