Simplifying Trig Expressions: Cos(6θ)

[ZincPony]

Homework Statement

Simplify the expression Cos(6θ)
Simplify means - the angle for all trigonometric functions in your answer is to be only θ.
Simplify in terms of sines and cosines
Simplify in terms of cosines only
Simplify in terms of sines only

Homework Equations

Basic Trig Identities (attachment)

The Attempt at a Solution

Im kind of lost to tell you the truth...
Maybe I am over thinking the difficulty of the problem and its a lot simpler then what I am making it out to be.

?? cos(2θ+2θ+2θ) ??

Just help me get started on this problem.
Guide me through the first couple of steps

 

[HallsofIvy]

Do equations have to be given? It seems to me that whoever gave you this problem expects you to know some basic trig identities yourself.

I would think that things like
sin(a+ b)= sin(a)cos(b)+ cos(a)sin(b)
cos(a+ b)= cos(a)cos(b)- sin(a)sin(b)
sin(2a)= 2sin(a)cos(a)
cos(2a)= cos^2(a)- sin^2(a)
would be very relevant!

For example, what do they give for
sin(3a)= sin(2a+ a)?

 

[ZincPony]

well the problem itself was did not come with identities.
what the textbook contains in terms of what we have covered in class i guess are the equations.

Added attachment