已知x+y=2,xy=—1⼀2,求x的4次方+y的4次方

2025-06-26 15:24:47
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回答1:

x的4次方+y的4次方=(x^2+y^2)^2-2x^2y^2=[(x+y)^2-2xy]^2-1/2=[4+1]^2-1/2=49/2