Electric potential ( with angle)

[dmack15]

Homework Statement

The electric potential of a region of space is V= 200 / sq root (x^2 + y^2), where x and y are in meters. What are the strength and direction of the electric field at (x,y) = (2m,1m)?

Homework Equations

The Attempt at a Solution

I took the negative derivative of V to find what the electric field would be. Then i substituted in (2,1)
200(2)(5)^-3/2 x + 200(5)^-3/2
=35.78x + 17.89 y

im having trouble figuring out where the angle should be. i do this a lot.

if i take the arctan or tan-1 of Ey/Ex

i get an angle of 26.6 degrees. Now is that 26.6 degrees ccw above the x-axis??
im having trouble figuring out where the final electric field will end up.
when i looked at the signs of x,y theyre both negative in the problem which means it would be quadrant 3.
even when i do 360-26.6 it ends in quadrant 4 which doesn't make sense

Please i don't need any help with the problem just with some help understanding the angle

 

[dmack15]

nevermind the x and y components are both positive so it falls in quadrant I.

thread closed