Hi,
I need help using the complex exponential to express
cos6x as a polynomial in terms of cosx
I don't know how to get it in terms of cosx without sinx.
Thankyou,
ArTiCk
where the expansion is done using the binomial theorem
and I'll leave the expansion and subsequent simplification for you.
I get ......
You should check that your answer gives 1 when you substitute x = 0. (Or that you get -1 when you substitute )
ps: I reserve the right for at least one error in this reply.