Question

assume that sin(pi/8) = (sqrt(2-sqrt2))/2
use identities to find the exact function value of:
cos(pi/8)
sin(17pi/8)

Answer 1

Ok do you know about the identity where sin(some angle) = sin(some angle + 2(pi))

Answer 2

yes, periodicity identity right ?

Answer 3

yup, the sin, cos, and tan functions are all periodic

Answer 4

sin(pi/8) = sin(17pi/8) it's the same thing

Answer 5

To find cos(pi/8), u can use the identity cos^2 + sin^2 =1

Answer 6

Oh okay got that one im kind of struggling with the first one lol.

Answer 7

Oh okay so it would be √(1 - ((2-√2)/2) ? o-o

Answer 8

you square your function, plug it in, then find cos^2

Answer 9

I'm not sure what you're doing. Just square sin(pi/8). You'll get

Answer 10

so you have cos^2 + (2-rad2/4) = 1

Answer 11

solve for cos^2, then rad it

Answer 12

Oh.

Answer 13

one sec, doing the problem.

Answer 14

redoing**

Answer 15

so it will be