Use the value of the trigonometric function to find $\cos~ t$ . $\cos ( - t ) = - \frac { 1 } { 4 }$
A) $\cos t = \frac { 1 } { 4 }$
B) $\cos t = - 4$
C) $\cos t = \infty$
D) $\cos t = 4$
E) $\cos t = - \frac { 1 } { 4 }$

Question

Use the value of the trigonometric function to find $\cos~ t$ .​ $\cos ( - t ) = - \frac { 1 } { 4 }$ ​
A) $\cos t = \frac { 1 } { 4 }$
B) $\cos t = - 4$
C) $\cos t = \infty$
D) $\cos t = 4$
E) $\cos t = - \frac { 1 } { 4 }$

Quizplus · Accepted Answer

The cosine function is an even function, meaning $\cos(-t) = \cos(t)$. Therefore, if $\cos(-t) = -\frac{1}{4}$, then $\cos(t) = -\frac{1}{4}$.

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