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先化简再求值(a-1+2/a+1)除以(a的平方+1),其中a=根号2-1

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搜狗问问

网友回答

[a-1+2/(a+1)]÷(a²+1)
=[(a-1)(a+1)/(a+1)+2/(a+1)]÷(a²+1)
=[(a²-1+2)/(a+1)]÷(a²+1)
=[(a²+1)/(a+1)]÷(a²+1)
=1/(a+1)
=1/(√2-1+1)
=1/√2
=√2/2



搜狗问问
原式=(a²-1+2)/(a+1)×1/(a²+1) =(a²+1)/(a+1)×1/(a²+1) =1/(a+1) =1/(√2-1+1) =1/√2 =√2/2
=(a^2-1+2)/(a+1) /(a^2+1) =1/(a+1) =1/(根号2-1+1) =根号2/2

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