化简求值:X^2-3X+1=0,求X+X^(-I)和X^2+X^(-2)的值

问题描述:

化简求值:X^2-3X+1=0,求X+X^(-I)和X^2+X^(-2)的值

X^2-3X+1=0
X²+1=3X
X+1/X=(x²+1)/x=3x/x=3
x²+1/x²=(X+1/X)²-2=3²-2=9-2=7
X+X^(-I)的值是3.
X^2+X^(-2)的值7.