- #1
springo
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Homework Statement
I make the product [tex]\cos(x)\cos(5x)[/tex] a sum of two cosines. I think this is called linearizing but please correct me if I'm wrong.
(I need it to find the n-th derivative of that function).
Homework Equations
The Attempt at a Solution
I know the answer is:
[tex]\frac{\cos(4x)+\cos(6x)}{2}[/tex]
- Thanks HP 50g ;) -
But how do I get to this result?
I think I should be using Moivre's formula but I get both sines and cosines in my formula.