Calculus/Calculus 1

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Expert: Alon Mandes - 9/26/2009


Question
I can't figure out how to prove the statement using the epsilon,delta definition of this limit.
Using 0<l x-a l< q then l f(x)-L l< E

Lim X approches 3  X^2+X-12/X-3 =7

Answer
1st let's note that :  (X^2+X-12)/(X-3)=(X-3)(X+4)/(X-3)=X+4 .
To prove that
Lim  X+4 = 7
X->3
Means that for every e>0 (small),there is a d>0 (small) such that |X-3|< d implies |X+4-7|<e.
Now, |X+4-7|<e means that |X-3|<e . So if we choose d=e , then we get :
|X-3|<d --> |X+4-7|<d --> |X+4-7|<e . Q.E.D

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".

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

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

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