<p>This is from barrons AP Physics C, I don't get how they simplify their answer:
Two positive charges +Q are located at (0,a) and (0,-a) Find the electric field along the x axis as a function of position.</p>
<p>This is what I did, I said the angle between the field and the y axis is going to be arctan(x/a) and the distance between the charge and point on the x axis is root(asquared+xsquared) so the electric field is going to be Q/(2(pi)(epsilon)(x^2+a^2))all this times sin(arctan(x/a))</p>
<p>The barron's book got my step, then simplified it to Qx/(2(pi)(epsilon)(x^2+a^2)^1.5)</p>
<p>How did they do this?</p>
<p>thanks for the help.</p>