AboutAlon Mandes Expertise Kind of questions I can answer : Limits, Derivatives, Integration, Implicit functions, continuousity, differentiation ,Extremum problems, Lagrange multipliers, Gradients, Surface integrals, Multi variables functions,Complex variables , Curves, Trajectory integrals & Vector analyse, infinite series &
convergence.
Kind of question I can't answer : Economics,Combinatorics.
Experience 1. I'm a team member of mathnerds (math site for answering questions)
2. I'm a team member in the Student's Union of the Technion, helping
students who have problems in mathematics.
3. 2 years of experience as a math teacher in college.
4. I give free homework help for high school students in
Mathematics & Physics.
Expert: Alon Mandes Date: 7/21/2008 Subject: Derivative of arc length
Question QUESTION: I had asked this question originally on the site:www.thestudentroom.co.uk But,I couldnot understand the answer as they said to apply chain rule of differentiation.Since the question is not like the general question on which we apply chain rule,I couldnot understand it.The attached picture on this question can be found on this link:http://www.thestudentroom.co.uk/attachment.php?attachmentid=56069&d=1216384477
The question goes like this-
In triangle PQR,
(chord PQ)^2=(PR)^2+(QR)^2=(delta x)^2+(delta y)^2
But,
how come this
(chord PQ/delta s(arc AP))^2*(delta s/delta x)^2=1+(delta y/delta x)^2
Please help me through this since I am facing lots of problem on this.
ANSWER: I'm sorry, but I was asked to enter user name & password. So I couldn't see the picture of the question. & I think I didn't completely understand the problem. So if you rather explain it more
with details or help me visualizing more clearly the problem.
Thank you.
Alon.
---------- FOLLOW-UP ----------
QUESTION: Now,here is the link,sorry for my blunder.
Answer Sorry, still didn't get any link. Any way, I'll try to build the missing details, I just have 2 questions :
The triangle PQR is not straight angle triangle..Right ?
& Where point A exists ? You measure dx & dy inside or outside
the triangle ? This information can assist me to visualize the question drawing. Thank you,
