Sunday, 1 July 2018

calculus - Finding limlimitsxrightarrow2dfracx38x2x2



I've done so many limit problems in calculus lately, but I can't wrap my mind around how to simplify this one in order to solve it:



lim



I understand the x^3-8 factors down to (x-2)(x^2+2x+4), but that still leaves us with
\lim_{x\rightarrow 2} \dfrac{(x-2)(x^2+2x+4)}{x^2-x-2},
which I can't seem to find a way to simplify so that the denominator is not equal to 0.



In case anyone figures out themselves, the answer is 4 (I was given the answer - this is on a review sheet for an upcoming exam). Also, I tagged this as homework, even though it is not technically homework.



So if anyone could help point me in the right direction here, that would be very helpful.


Answer



Hint: Note that x^2-x-2=(x-2)(x+1).


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