来自罗平亚的问题
a+b=4,a^2+b^2=10,求a^4+b^4的值
a+b=4,a^2+b^2=10,求a^4+b^4的值
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2020-02-08 09:30
a+b=4,a^2+b^2=10,求a^4+b^4的值
a+b=4,a^2+b^2=10,求a^4+b^4的值
(a+b)^2=4*4
a^2+2ab+b^2=16因为a^2+b^2=10
2ab=16-10
2ab=6
ab=3
a^4+b^4
=a^4+2a^2b^2+b^4-2a^2b^2
=(a^2+b^2)^2-2a^2b^2
=10^2-2*3^2
=100-2*9
=82