I cant get this. Express cos(7x) + cos(3x) as a product of trigonometric functions.
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Originally Posted by dazedandmathfused I cant get this. Express cos(7x) + cos(3x) as a product of trigonometric functions. List of trigonometric identities - Wikipedia, the free encyclopedia
Okay but i cant get the answer i dont know how
Write cos(7x) + cos(3x) as cos(5x+2x) + cos(5x-2x). Use angle addition & subtraction identities for cosine.
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