题目内容
(2)命题“x∈R,x2+1<0”的否定是_______.
(1)?x∈R,x2-x+3≤0 (2)x∈R,x2+1≥0
(1)命题“x∈R,x2-x+3>0”的否定是_________.
(2)命题“x∈R,x2+1<0”的否定是_________.