Given:
cos 120°
To find:
The exact value of cos 120° in simplest form with a rational denominator.
Solution:
We have,
It can be written as
![[\because \cos (90^\circ-\theta)=-\sin \theta]](https://tex.z-dn.net/?f=%5B%5Cbecause%20%5Ccos%20%2890%5E%5Ccirc-%5Ctheta%29%3D-%5Csin%20%5Ctheta%5D)
![[\because \sin 30^\circ=\dfrac{1}{2}]](https://tex.z-dn.net/?f=%5B%5Cbecause%20%5Csin%2030%5E%5Ccirc%3D%5Cdfrac%7B1%7D%7B2%7D%5D)
Therefore, the exact value of cos 120° is 
.
Answer:
BCD = 60
ABD - 90
Step-by-step explanation:
BCD)
BC and CD are the same length on in the circle, they are the radius. Therefor, all angles will be the same at 60
ABD)
All angles together are 180
You know 2 Angles, A at 30 and D at 60
180 - 30 - 60 = Angle B
90 = Angle B
X= 28
explanation: pythagorean theorem
Answer:
Step-by-step explanation:
f(-9) = 25
g(-1) = 21
It is 132 inches...............
