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a+b=1 a的平方+b的平方=2
求:a的5方+b的5方..
速度解决````
人气:468 ℃ 时间:2020-01-30 06:31:36
解答
a+b=1,(a+b)^2=1a^2+b^2+2ab=1因为a^2+b^2=2,所以a^2+b^2+2ab=2+2ab=1ab=-1/2(a^2+b^2)^2=a^4+b^4+2(ab)^2=a^4+b^4+1/2=2^2a^4+b^4=7/2(a+b)(a^4+b^4)=1*7/2a^5+b^5+ab^4+a^4b=7/2a^5+b^5+ab(a^3+b^3)=7/2a^5+b^5-1/...
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