Finding domain of a function

Question

Finding the domain of the function

$$f(x)=\frac{3\sqrt{x}}{x^2-5x-14}$$

My working out

First I factorise the denominator

$$f(x)=\frac{3\sqrt{x}}{(x-7)(x+2)}$$

Therefore the Domain is bigger than 0 and not equal to 7.

$(0,7], [7,\infty)$

Is my answer correct?

Almost, just your notation is off. You mean the domain is $[0,7)\cup (7,\infty)$, to include $0$ in the domain and exclude $7$. — Ian Coley, Mar 28 '13 at 00:06
WolframAlpha will tell you the domain of a function: http://www.wolframalpha.com/input/?i=domain+of+3sqrt%28x%29%2F%28%28x-7%29%28x%2B2%29%29 — Mark McClure, Mar 28 '13 at 01:15

score 3 · Accepted Answer · answered Mar 28 '13 at 00:06

3

7 is not in the domain, but 0 is, so you should write your answer like this: $[0,7)\cup (7,\infty)$.

answered Mar 28 '13 at 00:06

icurays1

1 Answers1