回複:請幫忙,一道數學題

回答: 請幫忙,一道數學題瓊島春蔭2010-09-05 14:23:06

(x+1/x)^2=9, ==>
x^2+1/x^2=7
(x^2+1/x^2)^2=49==>
x^4+1/x^4 = 47

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