Evaluate the expression.Round your result to two decimal places. $\arccos \left( - \frac { 2 } { 3 } \right)$
A)0.30
B)1.30
C)4.30
D)3.30
E)2.30

Question

Evaluate the expression.Round your result to two decimal places.   $\arccos \left( - \frac { 2 } { 3 } \right)$ 
A)0.30
B)1.30
C)4.30
D)3.30
E)2.30

Quizplus · Accepted Answer

The arccos function, also known as the inverse cosine function, returns the angle whose cosine is the given number. The value of $\arccos \left( - \frac { 2 } { 3 } \right)$ falls in the second quadrant where cosine values are negative. The exact angle is not easily determined without a calculator, but it is known that the angle in radians will be between $\frac{\pi}{2}$ and $\pi$ (or 90 and 180 degrees). Using a calculator to find $\arccos \left( - \frac { 2 } { 3 } \right)$ gives a value of approximately 2.30 radians, which matches option E.

Evaluate the Expression arccos⁡(−23)\arccos \left( - \frac { 2 } { 3 } \right)arccos(−32​)

Evaluate the Expression $\arccos \left( - \frac { 2 } { 3 } \right)$