# A question on limits

by Manni
Tags: bisector, calculus, limit, math, secant
 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? Attached Thumbnails
 Mentor P: 18,061 We give P the coordinates (x,y). We know that P is on the parabola, so we know that $$P=(x,x^2)$$ Now, can you find the coordinates of the point Q??
 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?
 Mentor 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.
 P: 44 How do I show algebraically that Q approaches infinity as P approaches the origin?
Mentor
P: 18,061
 Quote by Manni 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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