已知X等于根号下3+根号下2分之根号下3-根号下2则X方-10X+1的值等于?
问题描述:
已知X等于根号下3+根号下2分之根号下3-根号下2则X方-10X+1的值等于?
答
X等于根号下3+根号下2分之根号下3-根号下2
x=(√3-√2)/(√3+√2)
=(√3-√2)^2/(√3+√2) (√3-√2)
=5-2√6
X方-10X+1
=x(x-10)+1
=(5-2√6)(5-2√6-10)+1
=-(5-2√6)(5+2√6)+1
=-(25-24)+1
=-1+1
=0