Question

Trig questions- sin, cos, tan

Answer 1

@jim_thompson5910 can you help me out?

Answer 2

@RadEn

Answer 3

pi/4 obviously since that is listed as the answer
then the (sqrt2/2, sqrt2/2) would repeat at angle 3pi/4 but since it is in the 2nd quadrant the cos part would be negative so that won't work
then (sqrt2/2, sqrt2/2) comes up again at 5pi/4 -- this time quadrant 3 both the cos and sine part are negative....that should look like a pattern

Answer 4

so you're saying the answer is pi/4 but not the other 2 @kantalope

Answer 5

well part of what I'm saying now is that I didn't read the question very well sorry.... it is looking just for the sin part being positive, yes? Positive sin is in Q1 and Q2...so that part where I say that won't work....really it does

Answer 6

If you google images "unit circle" you can see some that are all filled in and see how the pattern works

Answer 7

@.Sam. help?

Answer 8

pi/4 = (sqrt2/2, sqrt2/2)
3pi/4 = (-sqrt2/2, sqrt2/2)
5pi/4 = (-sqrt2/2, -sqrt2/2)
7pi/4 = (sqrt2/2, -sqrt2/2)

t
sin is the y component and second point each bracket set up as (x,y) so sin is positive sqrt2/2 at pi/4 and 3pi/4

Answer 9

thanks for the help...i learned this a couple months back and im trying to refresh the material.