I have the function: y(t) = (cos(300πt) + sin(500πt))^3
I need too expand the expression of y to get a sum of cosines with positive frequencies. Using
trigonometric identities find the frequencies of resulting sine waves.Can someone help me with that?
Thank you
Hello qwerty321Using to stand for and for :
Now make repeated use of the following identities:
So, for example:
And the second term is:
Similarly with the last two terms. Finally, if you need to get an expression in terms of cosine only, you could use .
Grandad