cos(4pi/3)

find exact value as a fraction. No calculator.

Question

cos(4pi/3)

find exact value as a fraction. No calculator.

anonymous · Answer

@hartnn

hartnn · Answer

isn't 4pi/3 an angle in unit circle ?

anonymous · Answer

yes it is !!! look at you. you are a genius!!! so -1/2 (:

hartnn · Answer

thats correct.
i mean -1/2 is correct :P

anonymous · Answer

hahhahaha sure thats what you meant (:

anonymous · Answer

idk how i come up with -1/2...

hartnn · Answer

i though you came up with -1/2 by looking at x co-ordinate at 4pi/3 angle in unit circle....

anonymous · Answer

yes i do. but that is like memorization....
i dont have the math behind it. does that makes sense?

anonymous · Answer

you don't have to explain it. (: i think i will save that for my teacher.

hartnn · Answer

its good to remember sin and cos values of standard angles.

anonymous · Answer

Thank you sooooo much. you have been great! 
when i get on here again needing help i will be sure to find you ! (:

anonymous · Answer

kamehameha my friend.. (: 
have a goodnight.

hartnn · Answer

if i am online i'll surely help :)
you too have good night and sweet dreams :)

anonymous · Answer

well how often are you on here?!!

hartnn · Answer

few hours a day,when i am free...not fixed when

anonymous · Answer

:O ohhh no. what will i ever do?!

hartnn · Answer

there are so many people here who will help you, don't worry :)

anonymous · Answer

not ppls wiff 99 :O and ppls that are geniussss.

hartnn · Answer

not necessary that genius ppl have 99 SS, many geniuses have less SS...

anonymous · Answer

take the compliment punk :p

anonymous · Answer

hahaha (: the testimonies speak for themselves.

hartnn · Answer

compliment taken ... thanks :)

anonymous · Answer

(: sweet dreams.