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Calculus/Derivatives (dA/dd & dA/dC

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Expert: Alon Mandes - 10/15/2008


Question
Here is my question:
Rate of Change of the Area of a circle with respect to
a) diameter
b) circumference

Answer
As we know the area of the circle is : A=πr^2. We know that d=2r
("d is the diameter") So A(d)=πd^2/4 -> dA/dd=A'(d)=πd/2.
The Circumference of the circle is C=2πr -> r=C/2π. So the area is
A(C)=πC^2/4π^2=C^2/4π -> dA/dC=A'(c)=C/2π.

Alon.

Calculus

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Alon 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 ,Multi variables Integrals,Complex variables ,Complex functions, Curves, Trajectory integrals & Vector analyse,Divergence,Rotor & word problems. Kind of question I can't answer : Economics,Combinatorics,infinite series & convergence ,Statistics & Probabilities .

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. 5. I teach part time in collage the subjects : "Digital Signal Processing" , "Random Signals & Noise" , "Complex Functions".

Organizations
Hi-Tech company : GSM4VOIP ; job possition : Algorythm developer.

Education/Credentials
M.A in Mathematics & Bs.c in Electronics.

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