化简求值(1/(x-y)-1/(x+y))/(2y/(x^2-xy+y^2))其中x=2,y=-1
化简求值(1/(x-y)-1/(x+y))/(2y/(x^2-xy+y^2))其中x=2,y=-1化简求值(1/(x-y)-1/(x+y))/(2y/(x^2-xy+y^...
化简求值(1/(x-y)-1/(x+y))/(2y/(x^2-xy+y^2))其中x=2,y=-1 化简求值(1/(x-y)-1/(x+y))/(2y/(x^2-xy+y^2))其中x=2,y=-1 化简求值(1/(x-y)-1/(x+y))/(2y/(x^2-xy+y^2))其中x=2,y=-1
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(1/(x-y)-1/(x+y))/(2y/(x^2-xy+y^2))
=(2y/(x+y)(x-y))/(2y/(x^2-xy+y^2))
=(x^2-xy+y^2)/(x+y)(x-y)
=(x+y)(x^2-xy+y^2)/(x+y)^2(x-y)
=(x^3+y^3)/(x+y)^2(x-y)
=[2^3+(-1)^3]/(2-1)^2(2+1)
=7/3
如果不懂，请追问，祝学习愉快！
=(2y/(x+y)(x-y))/(2y/(x^2-xy+y^2))
=(x^2-xy+y^2)/(x+y)(x-y)
=(x+y)(x^2-xy+y^2)/(x+y)^2(x-y)
=(x^3+y^3)/(x+y)^2(x-y)
=[2^3+(-1)^3]/(2-1)^2(2+1)
=7/3
如果不懂，请追问，祝学习愉快！
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