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A question on limits

by Manni
Tags: bisector, calculus, limit, math, secant
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Manni
#1
Oct25-11, 06:38 PM
P: 44
I need help with this question. I understand that logic behind it; as P approaches O the value the right bisector Q reaches it's maximum. I don't know how to show this algebraically however. Help?
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micromass
#2
Oct25-11, 06:51 PM
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P: 18,061
We give P the coordinates (x,y). We know that P is on the parabola, so we know that

[tex]P=(x,x^2)[/tex]

Now, can you find the coordinates of the point Q??
Manni
#3
Oct25-11, 06:57 PM
P: 44
Ok, so the bisector would intersect P at point x/2. Because I know that the x coordinate on Q is 0, how would I find it's y?

micromass
#4
Oct25-11, 07:07 PM
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P: 18,061
A question on limits

Answer the following steps:

- Find the midpoint M between 0 en P.
- Find the equation of the line L going through 0 and P
- Find a vector perpendicular to the line L
- Construct the equation of the line R going through M and perpendicular through L
- Find Q as the intersection between R and the y-axis.

All of these questions involve nothing more than 10th grade geometry. So you should be able to complete these easily.
Manni
#5
Oct25-11, 11:06 PM
P: 44
How do I show algebraically that Q approaches infinity as P approaches the origin?
micromass
#6
Oct26-11, 10:18 AM
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P: 18,061
Quote Quote by Manni View Post
How do I show algebraically that Q approaches infinity as P approaches the origin?
It doesn't approach infinity.

Did you find the expression for Q?


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