How do you find the sine, cosine, and tangent of (-4pi)/3 radians?

1 Answer
Jul 4, 2018

#sin ((-4 pi)/3) = 1/2#
#cos ((-4 pi)/3) = sqrt(3)/2#
#tan((-4 pi)/3) = sqrt(3)/3#

Explanation:

Given: #(-4 pi)/3#

Add #2 pi# to find the positive equivalent angle:

#(-4 pi)/3 + (6 pi)/3 = (2 pi)/3#

#(2 pi)/3# is in the 2nd quadrant. The reference angle is #pi/3 = 60^@#

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#sin ((2 pi)/3) = 1/2#

#cos ((2 pi)/3) = sqrt(3)/2#

#tan ((2 pi)/3) = 1/sqrt(3) * sqrt(3)/sqrt(3) = sqrt(3)/3#