Limit of Lim h->0 ((2+h^2) - 8)/h

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SUMMARY

The limit of the expression \(\lim_{h \to 0} \frac{(2+h)^3 - 8}{h}\) evaluates to 12, as demonstrated through algebraic manipulation. The original expression \(\frac{(2+h)^2 - 8}{h}\) was incorrectly stated, leading to confusion regarding its limit. By expanding \((2+h)^3\) and simplifying, the limit is clearly defined and equals 12. This conclusion is essential for understanding limits in calculus.

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I saw my professor solve for the limit of ((2+h)2 - 8)/h as h approaches 0 and it was defined, but for the life of me I can't remember how. Everyone I have asked can't seem to figure it out either, so I was hoping someone here could explain.
 
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Arixal said:
I saw my professor solve for the limit of ((2+h)2 - 8)/h as h approaches 0

I'm going to assume the thread title is a typo.

and it was defined

Hint: let ##h = 0.1, 0.01, 0.001, \ldots## and manually calculate the expression for each ##h##.
 
Arixal said:
I saw my professor solve for the limit of ((2+h)2 - 8)/h as h approaches 0 and it was defined, but for the life of me I can't remember how. Everyone I have asked can't seem to figure it out either, so I was hoping someone here could explain.


You wrote

$$\frac{(2+h)^2-8}{h}$$

and the limit of this thing when \,h\to 0\, doesn't exist. But perhaps you meant

$$\lim_{h\to 0}\frac{(2+h)^3-8}{h}=\lim_{h\to 0}\frac{8+12h+6h^2+h^3-8}{h}=\lim_{h\to 0}\;(12+6h+h^2)=12$$

DonAntonio
 

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