Use a calculator to evaluate the trigonometric function. Round your answer to four decimal places. (Be sure the calculator is set in the correct angle mode.) $\sec 225 ^ { \circ }$
A) $\sec 225 ^ { \circ } \approx - 1.4142$
B) $\sec 225 ^ { \circ } \approx - 1.0475$
C) $\sec 225 ^ { \circ } \approx 0.0475$
D) $\sec 225 ^ { \circ } \approx - 0.4142$
E) $\sec 225 ^ { \circ } \approx 1.0475$

Question

Use a calculator to evaluate the trigonometric function. Round your answer to four decimal places. (Be sure the calculator is set in the correct angle mode.) $\sec 225 ^ { \circ }$ 
A) $\sec 225 ^ { \circ } \approx - 1.4142$
B) $\sec 225 ^ { \circ } \approx - 1.0475$
C) $\sec 225 ^ { \circ } \approx 0.0475$
D) $\sec 225 ^ { \circ } \approx - 0.4142$
E) $\sec 225 ^ { \circ } \approx 1.0475$

Quizplus · Accepted Answer

$\sec 225 ^{\circ} = \frac{1}{\cos 225 ^{\circ}}$. Since $\cos 225 ^{\circ} = -\frac{\sqrt{2}}{2}$, we have $\sec 225 ^{\circ} = \frac{1}{-\frac{\sqrt{2}}{2}} = -\frac{2}{\sqrt{2}} = -\sqrt{2} \approx -1.4142$. Thus, the best choice is $\boxed{	extbf{(A) } -1.4142}$.

Use a Calculator to Evaluate the Trigonometric Function sec⁡225∘\sec 225 ^ { \circ }sec225∘

Use a Calculator to Evaluate the Trigonometric Function $\sec 225 ^ { \circ }$