Question

数学题化简再求值（1/x-y+1/x+y）÷x^2 y^2/x^2-y^2,其中x=3,y=-√2

Answer 1

（1/x-y+1/x+y）÷x^2 y^2/x^2-y^2

＝（2x)/(x^2-y^2)÷(x^2 y^2)/(x^2-y^2)

＝（2x)/(x^2-y^2)÷(x^2-y^2)/(x^2 y^2)

＝2/(xy^2)

当x=3,y=-√2 时

2/(xy^2)

＝2/(3*2)

＝1/3

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