Cynthia Bell

2021-12-26

How do i solve cos (-60(degrees)) to exact values?

Karen Robbins

Beginner2021-12-27Added 49 answers

Explanation:

$\mathrm{cos}(-{60}^{\circ})$

first convert$60}^{\circ$ in radians just for the sake of convenience of problem solving in trigonometry. since $\pi \text{}\text{radian}\text{}={180}^{\circ}\Rightarrow {60}^{\circ}=\left(\frac{\pi}{3}\right)\text{}\text{radians}$

now, since$\mathrm{cos}(-\theta )=\mathrm{cos}\theta .$

so,$\mathrm{cos}(-\frac{\pi}{3})=\mathrm{cos}\left(\frac{\pi}{3}\right)=\frac{1}{2}$ (a standard value and should be memorised)

first convert

now, since

so,

jgardner33v4

Beginner2021-12-28Added 35 answers

Vasquez

Expert2022-01-08Added 669 answers

Thank you, it was very helpful

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