Without using a calculator, give the exact trigonometric function value with rational denominator.
-cos 30°
A) $\frac { 1 } { 2 }$
B) $\sqrt { 3 }$
C) $\frac { \sqrt { 2 } } { 2 }$
D) $\frac { \sqrt { 3 } } { 2 }$

Question

Without using a calculator, give the exact trigonometric function value with rational denominator.
-cos 30° 
A) $\frac { 1 } { 2 }$
B) $\sqrt { 3 }$
C) $\frac { \sqrt { 2 } } { 2 }$
D) $\frac { \sqrt { 3 } } { 2 }$

Quizplus · Accepted Answer

The cosine of 30 degrees is $\frac{\sqrt{3}}{2}$, which is a well-known value from the unit circle and trigonometric functions.

Without Using a Calculator, Give the Exact Trigonometric Function Value 12\frac { 1 } { 2 }21​

Without Using a Calculator, Give the Exact Trigonometric Function Value $\frac { 1 } { 2 }$