Question

How do you find the value of $\cos (300°)$?

Answer 1

Calculate the value trigonometric ratio at gievn angle:

Let $y$ be the value of $\cos (300°)$.

$\therefore y=\cos \left(300°\right)$

$\cos 300°=\cos \left(360°-60°\right)=\cos 60°\left[\because cos(360°-x°)=cosx°\right]$

We know that $\mathit{c}\mathit{o}\mathit{s}\mathbf{60}\mathbf{°}\mathbf{=}\frac{\mathbf{1}}{\mathbf{2}}$

$\therefore y=\cos \left(300°\right)$

$=\cos \left(60°\right)$

$=\frac{1}{2}$

Hence, the value of $\mathit{c}\mathit{o}\mathit{s}\mathbf{(}\mathbf{300}\mathbf{°}\mathbf{)}$ is $\frac{\mathbf{1}}{\mathbf{2}}$.