If you're going to use technology (Brainly) to solve this problem, you might find you get a quicker answer using the technology of your graphing calculator.
It is often convenient to cast the problem in the form f(θ) = 0. You can do that by adding 1 to both sides of the equation.
[tex] 4\sqrt{2}\cos{(\theta)}+4=0\\ \cos{(\theta)}+\dfrac{1}{\sqrt{2}}=0\qquad\mbox{divide by $4\sqrt{2}$}\\ \cos{(\theta)}=\dfrac{-\sqrt{2}}{2}\qquad\mbox{subtract $\dfrac{1}{\sqrt{2}}$}\\\\ \theta=\{\dfrac{3\pi}{4},\dfrac{5\pi}{4}\}\qquad\mbox{determine the corresponding angles} [/tex]
