Question

Find the value of cos (-2220°)

Answer 1

Step-by-step explanation:

To find: Value of cos 2220°

We have,

cos (-2220°) = cos 2220°

[∵ cos(-θ) = cos θ]

= cos [2160 + 60°]

= cos [360° × 6 + 60°]

= cos 60°

[Clearly, 2220° is in Ist Quadrant and the multiple of 360° is even]

Answer 2

The value of cos (-2220°) is $\frac{1}{2}$.

Step-by-step explanation:

Given:

cos (-2220°).

To Find:

The value of cos (-2220°) .

Formula Used:

$cos(-\theta)=cos\theta$    --------------formula no.01

$cos \ 60\textdegree=\frac{1}{2}$

Solution:

As given - $cos (-2220\textdegree)$

$cos (-2220\textdegree)$

Applying formula no.01.

$=cos (2220\textdegree)$

$=cos (2160\textdegree+60\textdegree)$

$=cos (360\textdegree\times6+60\textdegree)$

$=cos \ 60\textdegree$

$=\frac{1}{2}$

Thus,the value of cos (-2220°) is $\frac{1}{2}$.

PROJECT CODE#SPJ3