Can this project revolutionize surfing?

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Discussion Overview

The discussion revolves around evaluating the limit $\displaystyle \lim_{x \to 2}\dfrac{\sqrt{6-x}-2}{\sqrt{3-x}-1}$. Participants explore various steps and methods for solving this limit, including rationalizing the numerator and denominator, and they share their calculations and reasoning.

Discussion Character

  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • Some participants suggest that the first step should be to multiply by the conjugate to simplify the expression.
  • There is a proposal to rationalize the denominator, leading to a product of limits involving $\sqrt{3-x}+1$.
  • One participant calculates the limit after rationalizing the numerator and expresses uncertainty about the denominator becoming zero.
  • Another participant provides a detailed breakdown of the limit calculation, showing how terms cancel and lead to the final result of $\dfrac{1}{2}$.
  • Some participants express confusion about the steps taken and the correctness of the equations presented.

Areas of Agreement / Disagreement

Participants generally agree that the limit evaluates to $\dfrac{1}{2}$, but there is disagreement regarding the correctness of certain steps in the calculations and the handling of the denominator.

Contextual Notes

There are unresolved questions about the steps leading to the limit, particularly regarding the treatment of the denominator and the implications of terms approaching zero.

karush
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find limit $\displaystyle \lim_{x \to 2}\dfrac{\sqrt{6-x}{-2}}{\sqrt{3-x}-1}$
ok I presnume the first thing to do is mulitply by conjugate
 
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karush said:
find limit $\displaystyle \lim_{x \to 2}\dfrac{\sqrt{6-x}{-2}}{\sqrt{3-x}-1}$
ok I presnume the first thing to do is mulitply by conjugate
Yes, rationalizing the denominator would be step 1, resulting in

$\displaystyle \lim_{x \to 2} \dfrac{\sqrt{6-x}-2}{2-x} \cdot \lim_{x \to 2} (\sqrt{3-x}+1)$

step 2 would be rationalizing the numerator of the first limit in the product of limitsStep 2 would
 
skeeter said:
step 2 would be rationalizing the numerator of the first limit in the product of limits

$\displaystyle \left[ \dfrac{\sqrt{6-x}-2}{2-x}
\cdot \dfrac{\sqrt{6-x}+2}{\sqrt{6-x}+2}
\right]=\frac{\sqrt{-x+3}+1}{\sqrt{-x+6}+2}$
plug in 2
$\dfrac{\sqrt{-2+3}+1}{\sqrt{-2+6}+2}=\dfrac{1}{2}$
hopefully
 
karush said:
$\displaystyle \left[ \dfrac{\sqrt{6-x}-2}{2-x}
\cdot \dfrac{\sqrt{6-x}+2}{\sqrt{6-x}+2}
\right]=\frac{\sqrt{-x+3}+1}{\sqrt{-x+6}+2}$

?
 
skeeter said:
?
isn't $\dfrac{1}{2}$ the answer
 
yes, but that quoted equation you posted is not correct
 
$\:\left[\frac{\sqrt{6-x}-2}{2-x}\cdot \frac{\sqrt{6-x}+2}{\sqrt{6-x}+2}\right]:\quad \frac{\sqrt{6-x}-2}{2-x}$

as $x \to 2 $ then $=\dfrac{1}{2}$

however I didn't understand the denominator becoming 0
 
$\dfrac{\sqrt{6-x}-2}{2-x} \cdot \dfrac{\sqrt{6-x}+2}{\sqrt{6-x}+2} = \dfrac{(6-x)-4}{(2-x)(\sqrt{6-x}+2)} = \dfrac{\cancel{2-x}}{\cancel{(2-x)}(\sqrt{6-x}+2)} = \dfrac{1}{\sqrt{6-x}+2}$

return to the limit product from post #2

$\displaystyle \lim_{x \to 2} \dfrac{1}{\sqrt{6-x}+2} \cdot \lim_{x \to 2} (\sqrt{3-x}+1)$

$\dfrac{1}{4} \cdot 2 = \dfrac{1}{2}$
 
ok I see the calcular was making the 2nd fraction = to 1
...
A project I am developing ,,, its a lot more than I thot

https://dl.orangedox.com/EAwBaH3HAWsQbCDhxF
stn00.png

Surf the Nations back Entry
 
Last edited:

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