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题目已知在ΔABC中,内角A,B,C所对的边长分别为a,b,c,且B=π/3.若a/c+c/a=3,求sinAsinC.错解:a/c+c/a=3→sinA/sinC+sinC/sinA=3→sin^2A+sin^2C=3sinAsinC→sinAsinC=sin^2A+sin^2C/3,所以,只需求sin^2A+sin^2C/3的值。