Question

實數(shù)x,y,z滿足x²-2x+y=z-1且x+y²+1=0,試比較x,y,z的大小.

Answer 1

z≥y>x

x²-2x+y=z-1⇒z-y=(x-1)²≥0⇒z≥y;
x+y²+1=0⇒y-x=y²+y+1=+>0⇒y>x,故z≥y>x.