Question

某数与它的倒数和的平方等于4,这个数是______.

Answer 1

某数与它的倒数和的平方等于4,这个数是______.

注意：要过程.

(x+1/x)^2=4

x+1/x=+/-2

(1)x+1/x=2

x^2-2x+1=0

(x-1)^2=0

x=1

(2)x+1/x=-2

二边同乘x

x^2+2x+1=0

(x+1)^2=0

x+1=0

x=-1