1. ## Δy

Compute Δy and dy for x = 4 and dx = Δx = 1.

so i have found that dy = 1/4

and I know that Δy=f(x+Δx)-f(x)
and because x and Δx are given, we have
f(4+1)-f(4) = f(5)-f(4) right?
where do i go from here?

2. What's $f$? $dy=f^\prime(x)dx$.

3. what?
i don't know.
I have supplied all of the given information from the original problem

4. and i already figured out what dy is. i need help with change in y...

5. You need the derivative to find $dy$. You sure it wasn't given?

6. How did you find $dy$?

7. Originally Posted by vjelmy
Compute Δy and dy for x = 4 and dx = Δx = 1.

so i have found that dy = 1/4

and I know that Δy=f(x+Δx)-f(x)
and because x and Δx are given, we have
f(4+1)-f(4) = f(5)-f(4) right?
where do i go from here?
If the problem does not tell you what f(x) is, there is nothing else you can do! And if the problem does not tell you what f(x) is, how in the world did you determine that dy= 1/4?