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Calculus/Maths parametric equations

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Expert: Alon Mandes - 6/9/2010


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show that x=cos2x, y=sinxcosx is equal to x^2+4y^2=1

Answer
x²=Cos²(2β)
4y²=4Sin²(β)Cos²(β)=4[1-Cos(2β)][1+Cos(2β)]/4=[1-Cos(2β)][1+Cos(2β)]=1+Cos²(2β)=1-x² .
We got 4y²=1-x² , thus x²+4y²=1
I followed the rules :
1. Sin²(β)=[1-Cos(2β)]/2
2. Cos²(β)=[1+Cos(2β)]/2
You are welcom to prove them .

Alon.

Calculus

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Alon Mandes

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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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