当多项式m的平方+m-1=0 求值:m的3次方+2m的平方+2012

问题描述:

当多项式m的平方+m-1=0 求值:m的3次方+2m的平方+2012

2013

∵m^2+m-1=0,∴m^3+m^2-m=0,两式相加,得:m^3+2m^2-1=0,
∴m^3+2m+2012=2013。

∵m²+m-1=0
  ∴m²=1-m
  ∴m³+2m²+2012
  =m³+2m²+2012
  =m(1-m)+2m²+2012
  =m²+m+2012
  =1-m+m+2012
  =2013

m² + m - 1 = 0
m² + m = 1
m³ + 2m² + 2012
= (m³ + m²) + m² + 2012
= m(m² + m) + m² + 2012
= m + m² + 2012
= 1 + 2012
= 2013