SOLUTION: I have to find the exact value for this trigonometric expression. Help? :( cos^-1 (cos (7π/6)) = ??

Algebra ->  Trigonometry-basics -> SOLUTION: I have to find the exact value for this trigonometric expression. Help? :( cos^-1 (cos (7π/6)) = ??      Log On


   

Question 1030470: I have to find the exact value for this trigonometric expression. Help? :(
cos^-1 (cos (7π/6)) = ??
Found 2 solutions by fractalier, Cromlix:
Answer by fractalier(6550) About Me  (Show Source):
You can put this solution on YOUR website!
The inverse cosine undoes a cosine...thus
cos^(-1)(cos 7(pi)/6) = 7(pi)/6

Answer by Cromlix(4381) About Me  (Show Source):
You can put this solution on YOUR website!
Hi there,
cos^-1 = 1/cos(7π/6)
= -2√3/3
Hope this is what you want.