Question

Find sin θ if cot θ = - 4 and cos θ < 0.
I don't understand the Fundamental Identities.
Thank you.

Answer 1

I would watch this for the basics
http://www.khanacademy.org/math/trigonometry/v/basic-trigonometry

and this for the unit circle
http://www.khanacademy.org/math/trigonometry/v/unit-circle-definition-of-trig-functions-1

Answer 2

cot A = 1/tan A
if they tell you cot A = -4 then tan A= -1/4

Answer 3

Thank you!