Electric field from dipole potential using derivative

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
2 replies · 7K views
stargirl22
Messages
3
Reaction score
0
I am studying for a test and i can't figure out for the life of me how my book derived the solution for this problem I know it has to be basic i just don't see it...

An electric dipole consists of two charges of equal magnitude and opposite sign separated by a distance 2a... The dipole is along the x-axis and is centered at the origin.
calculate V and Ex if point P is located anywhere between the two charges.

I understand the concept of this, and have calculated V, which is [ (2*(Ke)*q*x) / ((a^2) - (x^2)) ] and i know how to start the problem of Ex...

Ex = - (dV/dx) = - [ (2*(Ke)*q*x) / ( (a^2) - (x^2) ) ...

But I can't remember or figure out for the life of me how they got

= - 2*(Ke)*q * [ { (a^2) + (x^2) } / { ( (a^2)-(x^2) )^2 } ]

Can Anyone please help? :D
 
Physics news on Phys.org
try using the quotient rule for the derivation! You will get it!