SOLUTION: Write the expression equivalent to cos 3 theta

Question 757630: Write the expression equivalent to cos 3 theta
Found 3 solutions by Alan3354, MathLover1, pmatei:
Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
Write the expression equivalent to cos 3 theta
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cos(3theta) = 4cos^3(theta) - 3cos(theta)

Answer by MathLover1(20855)   (Show Source): You can put this solution on YOUR website!

Answer by pmatei(79)   (Show Source): You can put this solution on YOUR website!

Replacing lines 2 and 3 into the first one and a bit of algebra:

If you want only cosine functions replace :

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