What is the domain and range of the given function f(x)= (x-1)/(x+3)?

1 Answer
Feb 18, 2017

Domain: (-oo, -3) U (-3, oo)
Range: (-oo, 1) U (1, oo)

Explanation:

Rational function: (N(x))/(D(x)) = (x-1)/(x+3):

Analytically, vertical asymptotes are found when you set D(x)=0:

x + 3 = 0; x = -3 so the vertical asymptote is at x = -3

Horizontal asymptotes are found based on the degree of the functions: (ax^n)/(bx^m) When n=m, y=a/b = 1

so the horizontal asymptote is at y = 1

You can see this from the graph:
graph{(x-1)/(x+3) [-10, 10, -5, 5]}