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