Step-by-step explanation:
[tex]6 \cos {}^{2} (x) + 4 \sin {}^{2} (x) = 5[/tex]
[tex]6(1 - sin {}^{2} x) + 4 \sin {}^{2} (x) = 5[/tex]
[tex]6 - 6 \sin {}^{2} (x) + 4 \sin {}^{2} (x) = 5[/tex]
[tex]6 - 2 \sin { }^{2} (x) = 5[/tex]
[tex] - 2 \sin {}^{2} (x) = - 1[/tex]
[tex] \sin {}^{2} (x) = \frac{1}{2} [/tex]
[tex] \sin(x) = \frac{1}{ \sqrt{2} } [/tex]
Take the arc Sine of the function
[tex]arcsin( \frac{1}{ \sqrt{2} } ) = \frac{\pi}{4} [/tex]
Finally, Sine is a periodic function so it has two answers within the interval (0, 2 pi)
Use the identity
[tex] \sin(x) = \sin(x + \pi) [/tex]
We know that
[tex] \sin( \frac{\pi}{4} ) = \frac{1}{ \sqrt{2} } [/tex]
so using the identity
[tex] \sin( \frac{\pi}{4} + \pi ) = \sin( \frac{5\pi}{4} ) [/tex]
So we have two answers.
[tex]( \frac{\pi}{4} )[/tex]
[tex]( \frac{5\pi}{4} )[/tex]
