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November 3rd, 2018, 07:34 AM   #1
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Hi I need to answer the following equation:

$\displaystyle \lim_{x\to2}$ (x³ + 3x - 1) =

x3 = x to the power of 3

Last edited by skipjack; November 3rd, 2018 at 10:37 AM.
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November 3rd, 2018, 09:51 AM   #2
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Show x to the power of 3 as x^3.

One way to answer this question is to use the laws of limits.

$\displaystyle \lim_{x \rightarrow a} f(x) = b, \ \lim_{x \rightarrow a} g(x) = c, \text { and } h(x) = f(x) + g(x) \implies \lim_{x \rightarrow a} h(x) = b + c.$

$\displaystyle \lim_{x \rightarrow a} f(x) = b, \ \lim_{x \rightarrow a} g(x) = c, \text { and } h(x) = f(x) - g(x) \implies \lim_{x \rightarrow a} h(x) = b - c.$

$\displaystyle \lim_{x \rightarrow a} f(x) = b, \ \lim_{x \rightarrow a} g(x) = c, \text { and } h(x) = f(x) * g(x) \implies \lim_{x \rightarrow a} h(x) = bc.$

$\displaystyle \lim_{x \rightarrow a} f(x) = b, \ \lim_{x \rightarrow a} g(x) = c, \ c \ne 0, \text { and } h(x) = \dfrac{f(x)}{g(x)} \implies \lim_{x \rightarrow a} h(x) = \dfrac{b}{c}.$
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November 3rd, 2018, 10:06 AM   #3
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Okay, so what's the answer?

Last edited by skipjack; November 3rd, 2018 at 10:39 AM.
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November 3rd, 2018, 10:38 AM   #4
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What do you get by replacing each "x" in "x³ + 3x - 1" with "2" and evaluating the result?
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November 3rd, 2018, 11:50 AM   #5
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Originally Posted by raven2k7 View Post
Okay, so what's the answer?
The answer is that it's time for you to do some work for yourself.
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November 3rd, 2018, 12:59 PM   #6
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Informally, substitute x = 2

Formally, limit of a sum is sum of its summands limits, and limit of a product is product of its factors limits. limit x = 2.
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November 3rd, 2018, 01:32 PM   #7
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Okay, so what's the answer?
lmao
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November 4th, 2018, 02:23 AM   #8
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Quote:
Originally Posted by zylo View Post
Informally, substitute x = 2

Formally, limit of a sum is sum of its summands limits, and limit of a product is product of its factors limits. limit x = 2.
by the way, none of those results were correct. lol
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November 4th, 2018, 02:57 AM   #9
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by the way, none of those results were correct. lol
This thread gets even funnier!
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November 4th, 2018, 04:35 AM   #10
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He is clearly clever enough that he doesn't need any help.
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