- #1
DrummingAtom
- 659
- 2
Homework Statement
Show that
[tex] E = \frac {q}{4\pi\varepsilon(z-\frac{1}{2}d)^2} - \frac{q}{4\pi\varepsilon(z+\frac{1}{2}d)^2}
[/tex]
is
[tex]E = \frac {q}{4\pi\varepsilon z^2} [(1-\frac{d}{2z})^{-2} - (1+\frac{d}{2z})^{-2}][/tex]
Homework Equations
The Attempt at a Solution
After getting a common denominator and subtracting I got
[tex] \frac {2qdz}{4\pi\varepsilon(z^4-\frac{1}{2}d^2z^2+\frac{1}{16}d^4)}[/tex]
Stuck completely at this point. I've tried working backwards but that is even more confusing. Any help would be appreciated. Thanks.