Question 174395: Find secθ if sinθ =-4/5 and 270 degrees< θ<360 degrees
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Find secθ if sinθ =-4/5 and 270 degrees< θ<360 degrees
------------
When sin is negatve and 270 < theta < 360, theta is in the 3rd quadrant
---------------
If sin = -4/5, y = -4 and r = 5
So, x = sqrt(25-16) = 9
But x is negative in the 3rd quadrant.
So sec(theta) = r/x = 5/-9 = -5/9
====================================
Cheers,
Stan H.
|
|
|
