Without using a calculator, give the exact trigonometric function value with rational denominator.
-$\cos 60 ^ { \circ }$
A) $\frac { 1 } { 2 }$
B) $\frac { \sqrt { 2 } } { 2 }$
C) $\sqrt { 3 }$
D) $\frac { \sqrt { 3 } } { 2 }$

Question

Quizplus · Accepted Answer

$\cos 60 ^ { \circ } = \frac { 1 } { 2 }$ is a well-known trigonometric value derived from the properties of an equilateral triangle.

Without Using a Calculator, Give the Exact Trigonometric Function Value cos⁡60∘\cos 60 ^ { \circ }cos60∘

Without Using a Calculator, Give the Exact Trigonometric Function Value $\cos 60 ^ { \circ }$