Figure 22-7a shows three particles with charges q1= +2Q,
q2=-2Q, and q3 = -4Q, each a distance d from the origin.
What net electric field E is produced at the origin?
The Attempt at a Solution
So i calculated the of each particles separately.
now ƩFx= [-E1cos(30)-E2cos(30) -E3cons(30)]1/(4∏ε0)
ƩFy= 2Q/d^2*sin(30)+2Q/d^2*sin(30) -4Qsin*(30)
this means that we have a net electric field on the negative x direction of -8Q/d^2 *cos(30)*(1/(4∏ε0)).
however, my book has the same answer but in the positive x direction. they used a different method to solved this.
I attached the book's answer.
what did i do wrong?