Question

the exact value of cos 2π/8 is?
a) radical 3/2
b) - radical 3 / 2
c) 1/2
d) -1/2

Answer 1

1/rad2

Answer 2

ya none of those answers are right

Answer 3

which isn't a option, umm stange. i think your question is wrong

Answer 4

rationalized denominator is sqrt(2)/2

Answer 5

but those are the answer that the textbook gives me

Answer 6

for one thing,
\[\frac{2\pi}{8}=\frac{\pi}{4}\]

Answer 7

yea or cos(45) in degrees

Answer 8

so maybe there is a typo in the question because as it is written the answer is
\[\frac{\sqrt{2}}{2}\]

Answer 9

wait guys, it's suppose to be 2pi/3

Answer 10

maybe you didn't type the question correctly, probably the options

Answer 11

lol

Answer 12

how'd i guess?

Answer 13

1/2

Answer 14

satellite, come back to my problem

Answer 15

-1/2

Answer 16

wait satellite how do i show work?

Answer 17

look at a cosine graph

Answer 18

dockworker how did you get -1/2?

Answer 19

i mean dockworker is right

Answer 20

find
\[\frac{2\pi}{3}\] on the attached cheat sheet. first coordinate on the unit circle will be cosine
it will be
\[-\frac{1}{2}\]

Answer 21

thanks guys :)