Solve the problem.
-If $f ( \theta ) = \cos \theta$ and $f ( a ) = - \frac { 1 } { 4 }$, find the exact value of $f ( - a )$.
A) $- \frac { 3 } { 4 }$
B) $\frac { 3 } { 4 }$
C) $\frac { 1 } { 4 }$
D) $- \frac { 1 } { 4 }$

Question

Quizplus · Accepted Answer

The cosine function is an even function, meaning $f(-\theta) = f(\theta)$. Therefore, if $f(a) = -\frac{1}{4}$, then $f(-a) = -\frac{1}{4}$ as well.

Solve the Problem f(θ)=cos⁡θf ( \theta ) = \cos \thetaf(θ)=cosθ And f(a)=−14f ( a ) = - \frac { 1 } { 4 }f(a)=−41​

Solve the Problem $f ( \theta ) = \cos \theta$ And $f ( a ) = - \frac { 1 } { 4 }$