当x取怎样的实数时下列各式在实数范围内有意义(1)√4+5x (2)x/1-x (3)√3x+2/x (4)x^2+1

问题描述:

当x取怎样的实数时下列各式在实数范围内有意义
(1)√4+5x (2)x/1-x (3)√3x+2/x (4)x^2+1

(1)√4+5x
4+5x>=0
x>=-4/5
(2)x/1-x
1-x≠0
x≠1
(3)√3x+2/x
(3x+2)x>=0,且x≠0
所以
x>0或x