SOLUTION: Express cos 128 degrees as a function of a positive acute angle. Thank you so much.

Algebra.Com
Question 1035979: Express cos 128 degrees as a function of a positive acute angle.
Thank you so much.

Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
Express cos 128 degrees as a function of a positive acute angle.
-----
128 is in QII where the cosine is negative
----
128 is 180-128 = 52 degrees above the x-axis
----
Reference angle is 52 degrees
cos(128) = -cos(52)
------------------
Cheers,
Stan H.
----------

RELATED QUESTIONS

Express as a function as a positive acute angle a) cos 110 b) sin 220 x) tan 160 Can (answered by Alan3354)
Express as a function as a positive acute angle a) cos -20 b) sin -50 c) tan -75 Can (answered by Alan3354)
Express as a function as a positive acute angle a)sin(π - 1.2) b)cos (π -... (answered by Alan3354)
Express tan 225 degrees as a function of a positive acute... (answered by rapaljer)
express tan150 degrees as a function of a positive acute... (answered by oscargut)
Express as a function of a positive acute angle a) cos 140 b) sin 235 c) tan -65 d)... (answered by Alan3354)
express ctn -249 degrees as the same function of a positive acute angle. (answered by kietra)
express tan 221 degrees as the same function of a positive acute... (answered by kietra)
express sec -123 degrees as the same function of a positive acute... (answered by kietra)