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 November 3rd, 2018, 08:34 AM #1 Newbie   Joined: Sep 2018 From: Spain Posts: 19 Thanks: 0 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 11:37 AM. November 3rd, 2018, 10:51 AM #2 Senior Member   Joined: May 2016 From: USA Posts: 1,310 Thanks: 552 Show x to the power of 3 as x^3. One way to answer this question is to use the laws of limits. $\displaystyle \lim_{x \rightarrow a} f(x) = b, \ \lim_{x \rightarrow a} g(x) = c, \text { and } h(x) = f(x) + g(x) \implies \lim_{x \rightarrow a} h(x) = b + c.$ $\displaystyle \lim_{x \rightarrow a} f(x) = b, \ \lim_{x \rightarrow a} g(x) = c, \text { and } h(x) = f(x) - g(x) \implies \lim_{x \rightarrow a} h(x) = b - c.$ $\displaystyle \lim_{x \rightarrow a} f(x) = b, \ \lim_{x \rightarrow a} g(x) = c, \text { and } h(x) = f(x) * g(x) \implies \lim_{x \rightarrow a} h(x) = bc.$ $\displaystyle \lim_{x \rightarrow a} f(x) = b, \ \lim_{x \rightarrow a} g(x) = c, \ c \ne 0, \text { and } h(x) = \dfrac{f(x)}{g(x)} \implies \lim_{x \rightarrow a} h(x) = \dfrac{b}{c}.$ Thanks from topsquark November 3rd, 2018, 11:06 AM #3 Newbie   Joined: Sep 2018 From: Spain Posts: 19 Thanks: 0 Okay, so what's the answer? Last edited by skipjack; November 3rd, 2018 at 11:39 AM. November 3rd, 2018, 11:38 AM #4 Global Moderator   Joined: Dec 2006 Posts: 21,105 Thanks: 2324 What do you get by replacing each "x" in "x³ + 3x - 1" with "2" and evaluating the result? November 3rd, 2018, 12:50 PM   #5
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 Originally Posted by raven2k7 Okay, so what's the answer?
The answer is that it's time for you to do some work for yourself. November 3rd, 2018, 01:59 PM #6 Banned Camp   Joined: Mar 2015 From: New Jersey Posts: 1,720 Thanks: 126 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. November 3rd, 2018, 02:32 PM   #7
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 Originally Posted by raven2k7 Okay, so what's the answer?
lmao November 4th, 2018, 03:23 AM   #8
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 Originally Posted by zylo 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 November 4th, 2018, 03:57 AM   #9
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 Originally Posted by raven2k7 by the way, none of those results were correct. lol November 4th, 2018, 05:35 AM #10 Math Team   Joined: Dec 2013 From: Colombia Posts: 7,696 Thanks: 2681 Math Focus: Mainly analysis and algebra He is clearly clever enough that he doesn't need any help. Tags limits Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Similar Threads Thread Thread Starter Forum Replies Last Post consigliere- Calculus 4 January 30th, 2013 06:54 AM math89 Calculus 2 January 26th, 2013 05:11 PM Arley Calculus 2 April 2nd, 2012 06:50 PM kadmany Calculus 9 March 18th, 2011 07:16 AM lilwayne Calculus 18 September 23rd, 2010 03:39 PM

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