Evaluate the trigonometric function.Round your answer to four decimal places.(Be sure the calculator is set in the correct angle mode. )
Sec 221°

A)-1.3250
B)-1.0250
C)-0.8250
D)-0.9250
E)-1.2250

Question

Evaluate the trigonometric function.Round your answer to four decimal places.(Be sure the calculator is set in the correct angle mode. ) ​
Sec 221°
​
A)-1.3250
B)-1.0250
C)-0.8250
D)-0.9250
E)-1.2250

Quizplus · Accepted Answer

We know that sec x = 1/cos x. 
Therefore, sec 221° = 1/cos 221° 
Using a calculator in degree mode, we get cos 221° ≈ -0.5736 
Thus, sec 221° ≈ 1/(-0.5736) ≈ -1.3250 (rounded to four decimal places) 
So, the best choice is A, which matches our calculated value.

Evaluate the Trigonometric Function