cosB=(a²+c²-b²)/2ac=3/4
b²=ac
代入得:(a-2c)×(2a-c)=0
a=2c或a=c/2
a=2c时:(b²=ac=2c²)
cosC=(a²+b²-c²)/2ab=(4c²+2c²-c²)/(c²×4倍根号2)=(5根号2)/8
sinB=根号下(1-cos²B)=(根号7)/4
sinC/c=sinB/b
sinC=c×sinB/b=(根号7)/4/(根号2)=根号14/8
cotC=cosC/sinC=(5根号2)/8/(根号14/8)=5(根号7)/7
a=c/2
同理