- #1

Find lim f(x+∆x) – f(x)/ ∆x

∆x→0

f(x)= x^2 – 4x

I have no idea what the delta means... I know in chem it means "a change in", but I don't know what to do with it here. My book doesn't explain it either. Please help! Thanks

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- Thread starter kendal12
- Start date

- #1

Find lim f(x+∆x) – f(x)/ ∆x

∆x→0

f(x)= x^2 – 4x

I have no idea what the delta means... I know in chem it means "a change in", but I don't know what to do with it here. My book doesn't explain it either. Please help! Thanks

- #2

mathmike

- 208

- 0

means as x approaches zero

or in other words the change in the value of x is getting so small that it is almost zero.

- #3

oh so it changes nothing?

- #4

or what am i supposed to do with the delta x value?

- #5

Tide

Science Advisor

Homework Helper

- 3,089

- 0

My book doesn't explain it either.

I seriously doubt that. For purposes of solving your problem and to get you accustomed to the concept why don't you just replace the [itex]\Delta x[/itex] with something more friendly looking like

- #6

- #7

- #8

Tide

Science Advisor

Homework Helper

- 3,089

- 0

You should have gotten [itex]2x - 4 + a[/itex]. Recheck your algebra.

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