Question

How do you evaluate sine -30 without a calculator?

Answer 1

Step one: recognize that sine is an odd function. What does this mean?
sine(-x)=-sin x

Answer 2

So, what's sin (-30) then?

Answer 3

think about triangles..

Answer 4

30 30 60

Answer 5

?

Answer 6

@parksbap , what is sin(-30) if sin(-x)=-sin(x)?

Answer 7

30

Answer 8

1/2

Answer 9

im sorry root3/2

Answer 10

No, what I'm trying to say is that sin(-x)=-sin x, so sin(-30)=-sin(30) . Does that make sense?

Answer 11

yes

Answer 12

So, just find -sin(30)