1.若不等式x^2+x+a>0的解集為R,實數(shù)a的取值范圍
(x+1/2)^2+a-1/4>0
a>1/4
2.k取何值時,不等式（k+1）x^2-2(k-1)x+3(k-1)≥0對于任何x∈R都成立
k+1>0
△=4(k-1)^2-4(k+1)(k-1)=-8(k-1)≤0
k≥1