已知x+(1⼀x)=2,求x^2+(1⼀x^2),x^4+(1⼀x^4)。

2025-01-05 17:07:46
推荐回答(2个)
回答1:

解:
x+(1/x)=2
[x+(1/x)]^2=2^2
x^2+2+(1/x)^2=4
x^2+(1/x)^2=2
[x^2+(1/x)^2]^2=2^2
x^4+2+(1/x)^4=4
x^4+(1/x)^4=2
即:
x^2+(1/x)^2=2
x^4+(1/x)^4=2

回答2:

x+(1/x)=2
所以 (3/2)x=2
所以 X=3
所以带入x^2+(1/x^2)得2^2+(1/2^2)=4.25
x^4+(1/x^4)=2^4+(1/4^4)=6562/81