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 
.
It’s equal’s 4n-12 because it’s multiplied by four then subtract 12 from the product
Are you sure this is college mathimatics bec this doesn't look like it
When changing fractions into decimals the whole number goes before the period and the fraction goes after.The denominator of the fraction will tell you whether or not you need to put any zeros before the numerator. If the denominator is 10 zeros are not needed.The end result is 7.2 and can be read as seven tenths.
1.04 kilograms
1 gram = .001 kilogram
2x520= 1040
1040 x .001 = 1.04 kilograms
