Question

to solve the equation 5 sin(2x) = 3cosx you should write it as
a. cosx (5sinx-3)=0
b. 5sinx+3cosx=0
c. cosx(10sin-3)=0

Answer 1

\[
5 \sin(2x) = 3\cos (x)\\
10 \sin(x) \cos(x) = 3 \cos(x)
\]
Here we use the formula
\[
\cos(2 a) = 2 \cos(a) \sin(a)
\]

Answer 2

Can you finish it now?

Answer 3

\[
5 \sin(2x) = 3\cos (x)\\
10 \sin(x) \cos(x) = 3 \cos(x)\\
10 \sin(x) \cos(x) - 3 \cos(x)=0\\
\cos(x)\left(10 \sin(x) - 3 \right)=0\\

\]