Evaluate the trigonometric function.Round your answer to four decimal places.(Be sure the calculator is set in the correct angle mode.)
$\cos ( - 1180 )$
A)-0.1736
B)0.3264
C)-0.0736
D)0.1264
E)0.2264

Question

Evaluate the trigonometric function.Round your answer to four decimal places.(Be sure the calculator is set in the correct angle mode.) 
 $\cos ( - 1180 )$  
A)-0.1736
B)0.3264
C)-0.0736
D)0.1264
E)0.2264

Quizplus · Accepted Answer

The cosine function is periodic with a period of 360 degrees, meaning $\cos(-1180^\circ) = \cos(-1180^\circ + 360^\circ \times k)$, where $k$ is an integer. For $-1180^\circ$, adding $360^\circ \times 4 = 1440^\circ$ gives $-1180^\circ + 1440^\circ = 260^\circ$. Thus, $\cos(-1180^\circ) = \cos(260^\circ)$, and calculating $\cos(260^\circ)$ gives approximately -0.1736.

Evaluate the Trigonometric Function cos⁡(−1180)\cos ( - 1180 )cos(−1180) A)-01736 B)0

Evaluate the Trigonometric Function $\cos ( - 1180 )$ A)-01736
B)0