# Limit notation question

## Main Question or Discussion Point

Limh→0+ (f(rh,h))/h
Is the f(rh,h) part the same as f(r+h)-f(h)? I have never seen this before and googling for a long time didn't help, there are no videos with this notation and it's not in my book so, am I just to assume it is? because it doesn't look like it should be the same.

Anyone know what f(rh,h) means? :)

Math_QED
Homework Helper
2019 Award
Limh→0+ (f(rh,h))/h
Is the f(rh,h) part the same as f(r+h)-f(h)? I have never seen this before and googling for a long time didn't help, there are no videos with this notation and it's not in my book so, am I just to assume it is? because it doesn't look like it should be the same.

Anyone know what f(rh,h) means? :)
Is f a function of 2 variables?

Is f a function of 2 variables?
Yes it is, how did you know? :P

Math_QED
Homework Helper
2019 Award
Yes it is, how did you know? :P
The notation suggested it.

The limit in your question is simply

$\lim_{h \to 0+} \frac{f(rh,h)}{h}$

This means that you evaluate $f$ in the point $(rh,h)$ and then take the limit after dividing the result by h.

The notation suggested it.

The limit in your question is simply

$\lim_{h \to 0+} \frac{f(rh,h)}{h}$

This means that you evaluate $f$ in the point $(rh,h)$ and then take the limit after dividing the result by h.
Oh it was this simple. I was afraid to get guess but thanks really helped me :)