Calculus Help (Differentiation?)

jennmaths

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Mar 11, 2021
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If g(x)=e^(2x), (g(h+1)-g(h-1))/h equals?
The following image present my work so far. I got e^(4) but the answer should be 2e^(2).
image.jpg
I’d appreciate any help!
 
If \(\displaystyle g(x)= e^{2x}\) then \(\displaystyle \frac{g(1+ h)- g(1- h)}{h}=\)
\(\displaystyle \frac{e^{2(1+h)}- e^{2(1- h)}}{h}= \frac{e^{2+ 2h}- e^{2- 2h}}{h}\)
\(\displaystyle = e^2\left(\frac{e^{2h}- e^{-2h}}{h}\right)\).

That is as simple as you can get it.
 
2 things.
1. Is it g(1-h) or g(h-1)
2. 2(1+h) = 2+2h not 2+ h
Fix those things and try again
1. It is g(1-h)
2. I had caught that and changed it the next step but forgot to rewrite it in the step before. It still leads me to e^(4).
 
1615594603527.png

You appear to be thinking that if you take the log of a difference, the result is the difference of the logs, though you correctly take the log of a product or quotient (on the inside, but not the division by h).

In addition, your presentation is poor, as you keep putting equal signs between things that are not equal.
 
Are you sure the question did not have 2h on the bottom?
Is the question to find the derivative from first principles, at x=1?

If [MATH]g(x) = e^{2x}[/MATH] then find [MATH]\lim\limits_{h \to 0}\frac{g(1+ h)- g(1- h)}{2h}[/MATH]
 
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