Thread: Graphing ln help

Hallo

Im a bit stuck.

I need to graph the function f(x) = ln(9-x^2) to find domain and range.
I assumed x > 3 as cant take ln of 0 or negative number. My graph came out looking like a nike tick.

However, when i checked my answer on graphics calculator, the graph is a u-shaped! with some negative values!
Im very confused. How do i get the right answer?

Thank you for your time.

LINK: graph of ln(9-x^2) ln(9-x^2) - Wolfram|Alpha

Hey razzatazz.

When we look at the domain, we typically look at the region where the input to the mapping (or function) is defined.

Now logarithms are only defined when the input is > 0 so this means that 9 - x^2 > 0 or x^2 < 9 which means x > -3 and x < 3.