已知(a+b)^2=5,(a-b)^2=1,求a^4+b^4

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已知(a+b)^2=5,(a-b)^2=1,求a^4+b^4
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已知(a+b)^2=5,(a-b)^2=1,求a^4+b^4
已知(a+b)^2=5,(a-b)^2=1,求a^4+b^4

已知(a+b)^2=5,(a-b)^2=1,求a^4+b^4
(a+b)^2-(a-b)^2=4ab=4 ab=1
(a+b)^2+(a-b)^2=2(a^2+b^2)=6 a^2+b^2=3
a^4+b^4
=(a^2+b^2)^2-2a^2*b^2
=(3)^2-2*(1)^2

(a+b)^2-(a-b)^2=4ab=4 ab=1
(a+b)^2+(a-b)^2=2(a^2+b^2)=6 a^2+b^2=3
a^4+b^4
=(a^2+b^2)^2-2a^2*b^2
=(3)^2-2*(1)^2
=7

(a+b)^2=5 ,(a-b)^2=1 (a+b)^2=a^2+b^2+2ab ,(a-b)^2= a^2+b^2-2ab
4ab= (a+b)^2-(a-b)^2=5^2-1^2=24 ab=6 a^2+b^2=(a+b)^2+ (a-b)^2=5^2+1^1=26
a^4+b^4 =(a^2+b^2)^2-2a2b^2= 26^2-2*4^2=644