If cos(3x)=sin(x+18°) what is the value of x

Use the identity,

This lets us write

and we can take the inverse cosine of both sides to get

where is any integer.

Solving for gives

-12 > a

step-by-step explanation:

-11 > 1 + a

subtract 1 from each side

-11-1 > 1-1+a

-12 > a