Expert: Steve Holleran - 9/23/2008

Question
State the domain of each function.

1) f(x) = Square Root(5 - x)

2) f(x) = -2x + 4 if x is less than or equal to 1
         3       if 1 < x < 4
         x + 1   if x is greater than or equal to 4

Answer
Hi Jeffrey,

For the first one, quantities under square roots must be >= 0, so

  5 - x >= 0 means 5 >= x or x <= 5 would be the domain.

For the second one, since f is defined on each interval, including x = 1 and x = 4, the domain would be all reals: (-inf, inf)

Steve