Question

If y=cos3xcos4x

Answer 1

Then y_n is?

Answer 2

I am guessing question is asking for nth differentiation

Answer 3

all hail @terenzreignz @zepdrix

Answer 4

Is it written like this by chance?
\[\huge y^{(n)}\]
That's usually how you would denote the \(\large n\)th derivative.

Answer 5

if it is differentiation use this formula:\[\cos p \cos q=\frac{1}{2} [\cos(p-q)+\cos(p+q)]\]

Answer 6

:)