Question

Use even and odd properties of the trigometric function to find the exact value of the cos (-150 degrees) what are the steps for this?

Answer 1

no i dont

Answer 2

hmm well its even so cos(-x) = cos(x)

Answer 3

do you know cos(150)?

Answer 4

this should be given on a unit circle

Answer 5

no. all i had was cos(-150) cos 150 degrees

Answer 6

but i dont know where to go from here

Answer 7

well this is just a angle you should have memorized

Answer 8

-sqrt(3)/2

Answer 9

what angle i should memorize?

Answer 10

30 45 60 90 120 135 180 210 225 240 270 300 315 330

Answer 11

you will notice that out of all these angles then numbers that go with them are 0,1,sqrt(2)/2,1/2, and sqrt(3)/2

Answer 12

so its not as bad as it looks, really if you get the first 4, the other are easy...

Answer 13

Ohhhhh i see what you mean.. learn them.

Answer 14

memorise them

Answer 15

i will make sure learn em*

Answer 16

http://www.youtube.com/watch?v=OBmhgiLi77k

Answer 17

this will make it easy