SOLUTION: Cos120°=-1/2
Algebra.Com
Question 1011485: Cos120°=-1/2
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Cos120°=-1/2
----
Yes.
Reference angle is 180-120 = 60 Degrees
cos(60) = 1/2
But cos is negative in QII
So cos(120) = -1/2
---------
Cheers,
Stan H.
------------
RELATED QUESTIONS
Cos120°=
(answered by Cromlix)
Simplify:
a)((cos120)/cos330)) - ((sin90)/cos315))
b) (sin^2 210)/ (3cos^2... (answered by drk)
express cos120 as a function of an angle in quadrant... (answered by jim_thompson5910)
Can you help me convert this to trigonometric form? {{{ z = -9/4 }}}+{{{ 9 sqrt( 3 )/4... (answered by Fombitz)
what is the exact value of cos120... (answered by anantha)
using cos3x= 4cos^3x -3cosx
find the general solution for cos3x+2cosx=0
Soln:... (answered by lwsshak3,deepakpradhan)
Find the exact value of the expression... (answered by stanbon)
Which is z₂⁴=256cis(240) equal to?
A.) 256(cos60 + i sin60)
B.) 256(cos120... (answered by Alan3354)
Which is z₂⁴=256cis(240) equal to?
A.) 256(cos60 + i sin60)
B.) 256(cos120... (answered by zoeyl4d2)