We have two graphs, one for f(x)=Cos2x and another for g(x)=3Sin2x
for both of them being between 0 - 180 deg.
The question is: Calculate the values for x where f(x) = g(x) if x \(\in \) (0;180)
Hello juriemagic!
\(f(x)=g(x)\\ cos\ 2x=3sin\ 2x\)
\(u=2x\)
\(cos\ u=3sin\ u\\ cos^2\ u =3(1-cos^2\ u)\\ cos^2\ u=3-3cos^2\ u\\ 4cos^2\ u=3\\ cos\ u=\sqrt{\frac{3}{4}}=\frac{\sqrt{3}}{2}\)
\(u=30^{\circ}\\ x=\frac{u}{2}\)
\(x=15^{\circ}\)
!
