课时提升作业(三)
一、选择题
1.(2013·厦门模拟)已知命题p:∀x∈R,x>sinx,则p的否定形式为( )
(A)∃x0∈R,x00 (B)∃x0∈R,x0≤sinx0
(C)∀x∈R,x≤sinx (D)∀x∈R,x
2．命题“∃(x,y),x,y∈R,2x+3y+3<0”的否定是( )
(A)∃(x,y),x,y∈R,2x+3y+3>0
(B)∃(x,y),x,y∈R,2x+3y+3≥0
(C)∀(x,y),x,y∈R,2x+3y+3≥0
(D)∀(x,y),x,y∈R,2x+3y+3>0
