SOLUTION: Please help me solve this equation: Find the domain of f, if f(x)=x=1 over x^3-4x The answer is: All real numbers except -2, 0, and 2

Algebra ->  Functions -> SOLUTION: Please help me solve this equation: Find the domain of f, if f(x)=x=1 over x^3-4x The answer is: All real numbers except -2, 0, and 2       Log On


   

Question 668510: Please help me solve this equation:
Find the domain of f, if f(x)=x=1 over x^3-4x
The answer is:
All real numbers except -2, 0, and 2
Found 2 solutions by swincher4391, ewatrrr:
Answer by swincher4391(1107) About Me  (Show Source):
You can put this solution on YOUR website!
%28x-1%29%2F%28x%5E3-4x%29
What is our domain of f? Well, maybe a better question is to ask what ISN'T in our domain of f? The only way for f(x) to be undefined. And how is f(x) undefined? We have some sort of division by 0. So, focus on the denominator for a minute.
Find all x such that x%5E3-4x+=+0
x^3-4x = x(x^2-4) = x(x-2)(x+2) so x = 0, 2, -2 are where our function is not defined.

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

f%28x%29+=+1%2F%28x%5E3-4x%29+=+1%2Fx%28x%5E2-4%29

Denominator x(x^2 - 4)  CANNOT = 0

this happens IF x = -2, 0, 2 

Therefore Domain is  All real numbers except -2, 0, and 2