Question

How do you write cos(6x) in terms of cosx and sinx?

Answer 1

im seeing this as \[\cos [2(3x)]\]

Answer 2

let a = 3x to make it easier \[\cos 2a\]
do you see it?

Answer 3

yes

Answer 4

@lgbasallote Please continue...

Answer 5

\[ (\cos 6x + i \sin 6x) = (\cos x + i \sin x)^6 \\
\text{expand it binomially and get it's real part.}\]

Answer 6

still need help? @shivraj

Answer 7

no thanks