Find the exact value of the expression if θ = 45°. Do not use a calculator.
-$$f ( \theta ) = \cos \theta \quad \text { Find } f ( \theta ) \text {. }$$
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 trigonometric identity.

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