Question

函数y=x-2/x-1的值域.y= √x +1的值域.y=（3x+2）/(x-1)的值域.

Answer 1

(1) y=(x-1-1)/(x-1)

=1-1/(x-1)

x-1≠0

1/(x-1)≠0

y≠1

（2）√x≥0

所以 y≥1

（3）y=(3x-3+5)/(x-1)

=3+5/(x-1)

x-1≠0

5/(x-1)≠0

y≠3