Question

1+cos(6x)=?

Answer 1

Do you want it down to cos(x) or will it be fine with cos(3x) too ?

Answer 2

\(\large\color{midnightblue}{ \rm 1+cos(6x)= }\)
\(\large\color{midnightblue}{ \rm 1+cos(3x+3x)= }\)
\(\large\color{midnightblue}{ \rm 1+cos^2(3x)-sin^2(3x)= }\)
\(\large\color{midnightblue}{ \rm 1-sin^2(3x)+cos^2(3x)= }\)
\(\large\color{midnightblue}{ \rm cos^2(3x)+cos^2(3x)= }\)
\(\large\color{midnightblue}{ \rm 2cos^2(3x). }\)

Answer 3

ok thank you :)

Answer 4

Anytime :)

Answer 5

you can take cos(3x) down, starting cos(2x+x), but then your answer will be too complicated.

Answer 6

ok, I understand it now

Answer 7

alright, good !