What is cos^-1(1/2)?

2 Answers
Aug 6, 2016

=60

Explanation:

cos^-1(1/2)
=60

Aug 7, 2016

pi/3, and (5pi)/3

Explanation:

arccos x = 1/2
Trig table of special arcs gives
cos x = 1/2 --> x = pi/3
Trig unit circle gives another arc x that has the same cos value -->
cos x = 1/2 --> x = - pi/3, or, x = (5pi)/3 (co-terminal)
Answers: pi/3 and (5pi)/3