How do you evaluate #cos(pi/12)# using the half angle formula?

Question

How do you evaluate #cos(pi/12)# using the half angle formula?

1 Answer

Impact of this question

15646 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-05-24T04:47:48

#sqrt(2 + sqrt3)/2#

Explanation:

Trig identity -->
#cos (pi/6) = sqrt3/2 = 2cos^2 (pi/12) - 1#
#2cos^2 (pi/12) = 1 + sqrt3/2 = (2 + sqrt3)/2#
#cos^2 (pi/12) = (2 + sqrt3)/4#
#cos (pi/12) = +- sqrt(2 + sqrt3)/2#.
Take the positive answer because cos (pi/12) is positive.

Science

Math

Humanities

... and beyond

How do you evaluate #cos(pi/12)# using the half angle formula?

1 Answer

Explanation:

Related questions

Impact of this question