SOLUTION: Find the domain of the function: f(x) = sqrt(13-x) Answer choices: A. (negative infinity, 13) or (13, infinity) B. (sqrt(7) , infinity) C. (negative infinity, 13] D. (nega

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Question 350743: Find the domain of the function:
f(x) = sqrt(13-x)
Answer choices:
A. (negative infinity, 13) or (13, infinity)
B. (sqrt(7) , infinity)
C. (negative infinity, 13]
D. (negative infinity, infinity)
*notice that C. has 13] we are using interval notation for this lesson which kind of confuses me.
Thanks so much!
Found 2 solutions by jim_thompson5910, haileytucki:
Answer by jim_thompson5910(35256) (Show Source):
You can put this solution on YOUR website!
Since you can't take the square root of a negative number, this means that . Solve for 'x' to get

So the domain is which in interval notation is (]

The basic idea with interval notation is that you're simply listing the boundaries of the set of numbers. In this case, the smallest number is negative infinity (ie there is no smallest number) and the largest number is 13 (and we're including 13)

If you need more help, email me at jim_thompson5910@hotmail.com

Also, feel free to check out my tutoring website

Jim

Answer by haileytucki(390) (Show Source):
You can put this solution on YOUR website!
f(x)=~(13-x)
The domain of an expression is all real numbers except for the regions where the expression is undefined. This can occur where the denominator equals 0, a square root is less than 0, or a logarithm is less than or equal to 0. All of these are undefined and therefore are not part of the domain.
(-x+13)<0
Solve the equation to find where the original expression is undefined.
x>13
The domain of the rational expression is all real numbers except where the expression is undefined.
x<=13_
-I,13 is your answer...so yes, C is correct due to the undefined regions