已知x+x分之1=-3,求x^4+x^4分之1的值

2025-03-11 05:33:05
推荐回答(2个)
回答1:

x^2+1/x^2
=(x+1/x)^2-2
=3^2-2
=7

x^4+1/x^4
=(x^2+1/x^2)-2
=7^2-2
=47

回答2:

x+1/x=-3,(x+1/x)^2=x^2+2+1/x^2=9
∴x^2+1/x^2=7,(x^2+1/x^2)^2=x^4+2+1/x^4=49,
∴x^4+1/x^4=47