Question

解不等式：x2+1分之2x+1大于0 x2+2分之2x+1大于1

Answer 1

(2x+1)/(x^2+1)>0,

x^2+1>0,上式变为2x+1>0,

2x>-1,

∴x>-1/2.

(2x+1)/(x^2+2)>1,

x^2+2>0,两边都乘以x^2+2,得

2x+1>x^2+2,

∴x^2-2x+1