已知X^2-11X+1=0 求x^2 + 1/x^2

问题描述:

已知X^2-11X+1=0 求x^2 + 1/x^2

X^2-11X+1=0
x-11+1/x=0
x+1/x=11
x^2+1/x^2=(x+1/x)^2-2=11^2-2=119