已知三角形ABC的外接圆半径为R,且满足2R(sin方A-sin方C)=(根号2a-b)sinB,(根号中为2,再乘a,最后减b),
问题描述:
已知三角形ABC的外接圆半径为R,且满足2R(sin方A-sin方C)=(根号2a-b)sinB,(根号中为2,再乘a,最后减b),
答
2.a/sinA=b/sinB=c/sinC=2R=2√=>a=2RsinA,b=2RsinB,c=2RsinC2√2(sin²A-sin²C)=(a-b)sinB=>4R²(sin²A-sin²C)=2R(a-b)sinB=>a²-c²=(a-b)b=>(a²+b²-c²)/2...