Question

1 + cos(18x) = _____.

Answer 1

I'm not really sure what they're looking for here...
I guess you could apply the Cosine Double Angle Formula,\[\Large\rm =1+\left[\color{orangered}{\cos(18x)}\right]\]\[\Large\rm =1+\left[\color{orangered}{2cos(9x)-1}\right]\]Which simplifies a lil bit,\[\Large\rm =2\cos(9x)\]

Answer 2

Woops that should be a square on the cosine >.< my bad.

Answer 3

\[\Large\rm =1+\left[\color{orangered}{2\cos^2(9x)-1}\right]\]

Answer 4

\[\Large\rm =2\cos^2(9x)\]

Answer 5

Is that what they wanted or no? :U

Answer 6

thank you

Answer 7

yes it is

Answer 8

cool c: