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Expert: Sherman D. - 7/20/2009


Question
Verify that the equation is an identity
sin(4x)=(4 sin x cos x)(2 cos^2 x-1)

Answer
sin(4x) = (4sin(x)cos(x))(2cos(x)^2 - 1)

(4sin(x)cos(x))(2cos(x)^2 - 1)

2sin(2x)cos(2x) = sin(2(2x)) or sin(4x)

another way of doing it is

sin(4x) = sin(2x + 2x) = sin(2x)cos(2x) + sin(2x)cos(2x) or 2sin(2x)cos(2x)

2(2sin(x)cos(x))(2cos(x)^2 - 1) or (4sin(x)cos(x))(2cos(x)^2 - 1)

more info at http://math2.org/math/trig/identities.htm

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Sherman D.

Expertise

I can answer questions dealing in mathematics of all kinds except for Physics and Calculus, but i can answer questions in Pre-Calculus and Chemistry. I can also answer questions in Recipes of all kinds. I can find games cheats/walkthroughs, but i can`t find a specific game online or offline. I can also do history and recipes for alcoholic beverages.

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Mathematics, Recipes, History, and Games.

Education/Credentials
High School graduated. I graduated with honors, and i was in Beta Club for a year and a half.

Awards and Honors
Principle's list and A and B honor roll in high school only.

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