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帮帮啦,很狡猾计算1/a-b-1/a+b+2b/a的2方+b的2方=
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帮帮啦,很狡猾
计算1/a-b-1/a+b+2b/a的2方+b的2方=
计算1/a-b-1/a+b+2b/a的2方+b的2方=
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答案和解析
1/(a-b)-1/(a+b)+2b/(a^2+b^2)
=[(a+b)-(a-b)]/[(a-b)(a+b)]+2b/(a^2+b^2)
=2b/(a^2-b^2)+2b/(a^2+b^2)
=2b[(a^2+b^2)-(a^2-b^2)]/[(a^2-b^2)(a^2+b^2)]
=2b*2b^2/(a^4-b^4)
=4b^3/(a^4-b^4)
=[(a+b)-(a-b)]/[(a-b)(a+b)]+2b/(a^2+b^2)
=2b/(a^2-b^2)+2b/(a^2+b^2)
=2b[(a^2+b^2)-(a^2-b^2)]/[(a^2-b^2)(a^2+b^2)]
=2b*2b^2/(a^4-b^4)
=4b^3/(a^4-b^4)
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