SOLUTION: Find the exact value of cos^-1{{{(cos(4PI/3))}}} the possible answers are a. -PI/3 b. PI/3 c. 2PI/3 d. 4PI/3 Thank you

Algebra ->  Trigonometry-basics -> SOLUTION: Find the exact value of cos^-1{{{(cos(4PI/3))}}} the possible answers are a. -PI/3 b. PI/3 c. 2PI/3 d. 4PI/3 Thank you       Log On


   

Question 73942This question is from textbook Algebra and Trigonomerty
: Find the exact value of cos^-1%28cos%284PI%2F3%29%29
the possible answers are
a. -PI/3
b. PI/3
c. 2PI/3
d. 4PI/3
Thank you This question is from textbook Algebra and Trigonomerty

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
The inverse cosine looks like this:
This function literally undoes the cosine function. If I plug in degrees into I get a value of 1/2 (ie If I take the inverse cosine of 1/2 I get 60. However, since the range of inverse cosine is [0,], we need to find a co-angle that is in the interval [0,] (in other words we need to reduce . So lets subtract from from

So

Note: if we evaluated we would get