How do you evaluate sin(arccos(-1/3))? Trigonometry Right Triangles Trigonometric Functions of Any Angle 1 Answer Nghi N. Oct 28, 2015 Evaluate sin (arccos (-1/3) Ans: +- (2sqrt2)/3 Explanation: cos x = -1/3 --> Radius of trig circle R = 3 sin^2 x = R^2 - cos^2 x = 9 - 1/9 = 8/9 --> sin x = +- (2sqrt2)/3 sin (arccos (-1/3)) = +- (2sqrt2)/3 Answer link Related questions How do you find the trigonometric functions of any angle? What is the reference angle? How do you use the ordered pairs on a unit circle to evaluate a trigonometric function of any angle? What is the reference angle for 140^\circ? How do you find the value of cot 300^@? What is the value of sin -45^@? How do you find the trigonometric functions of values that are greater than 360^@? How do you use the reference angles to find sin210cos330-tan 135? How do you know if sin 30 = sin 150? How do you show that (costheta)(sectheta) = 1 if theta=pi/4? See all questions in Trigonometric Functions of Any Angle Impact of this question 5066 views around the world You can reuse this answer Creative Commons License