Find the exact value of the expression if θ = 45°. Do not use a calculator.
-$f ( \theta ) = \cos \theta \quad$ Find $f ( \theta )$
A) $\frac { \sqrt { 3 } } { 3 }$
B) $\sqrt { 2 }$
C) $\frac { \sqrt { 2 } } { 2 }$
D) $- \frac { \sqrt { 2 } } { 2 }$

Question

Quizplus · Accepted Answer

The cosine of 45° is $\frac{\sqrt{2}}{2}$, which is a well-known value from the unit circle and trigonometric identities.

Find the Exact Value of the Expression If θ = f(θ)=cos⁡θf ( \theta ) = \cos \theta \quadf(θ)=cosθ

Find the Exact Value of the Expression If θ = $f ( \theta ) = \cos \theta \quad$