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What is the integral of cos 2x?

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grade83 | Student | eNoter

Posted April 1, 2011 at 2:50 PM via web

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What is the integral of cos 2x?

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted April 1, 2011 at 2:52 PM (Answer #1)

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We have to find the integral of cos 2x.

Int[ cos 2x dx]

let 2x = u

du = 2*dx

dx = (1/2)*du

=> Int [ cos u * (1/2) du]

=> (1/2) sin u + C

substitute u = 2x

=> (1/2) sin 2x + C

The required integral of cos 2x is (1/2)*sin 2x + C

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nvoron23 | Student, College Freshman | eNoter

Posted April 3, 2011 at 7:08 PM (Answer #2)

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integral is antiderivative of the function.

in this case, a derivative would use the chain rule, wherareas the antiderivative or the integral would use the same, except in the opposite direction.  Thus, Integral of of cos 2x is (1/2)*sin 2x

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