令2S=2a²﹢2b²﹢2c²﹣2ab﹣2ac﹣2bc,则
2S=(a-b)²﹢(a-c)²﹢(b-c)²=﹛1 ∕ (2m﹢1)(2m﹢2)﹜﹢﹛1 ∕ (2m﹢2)(2m﹢3)}﹢﹛1 ∕ (2m﹢2)(2m﹢3)}=(6m﹢6) ∕ (2m﹢1)(2m﹢2)(2m﹢3)
S=( 3m﹢3) ∕ (2m﹢1)(2m﹢2)(2m﹢3)=3 ∕ 2(2m﹢1)(2m﹢3)
令2S=2a²﹢2b²﹢2c²﹣2ab﹣2ac﹣2bc,则
2S=(a-b)²﹢(a-c)²﹢(b-c)²=﹛1 ∕ (2m﹢1)(2m﹢2)﹜﹢﹛1 ∕ (2m﹢2)(2m﹢3)}﹢﹛1 ∕ (2m﹢2)(2m﹢3)}=(6m﹢6) ∕ (2m﹢1)(2m﹢2)(2m﹢3)
S=( 3m﹢3) ∕ (2m﹢1)(2m﹢2)(2m﹢3)=3 ∕ 2(2m﹢1)(2m﹢3)