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$\cos(2\pi50t)+2\cos(2\pi150t)$
Can these be further simplified?
What is the addition of this called? Trigo identity?

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    that is just part of the equations. but the full expression is similiar, its the result of multiplication of 2 equations. So I'm wondering can I simply add them together? and become 3cos(2$\pi$200t)?2012-02-25

1 Answers 1

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Rewrite expression into :

$\cos (100 \pi t)+2 \cos(300 \pi t)$

Now use Triple-angle formulae :

$\cos 3\theta=4\cos^3 \theta -3\cos \theta$