# Math Help - Integral for an electric field

1. ## Integral for an electric field

I am in physics and my calculus skills are rusty. I need to take the integral of the following:

(d) /(y^2 + d^2)^(3/2) dy I know that I use the power rule and I end up with (y^2 + d^2)^(-1/2) / (-1/2) and then since I have the d to intergrate should that not be d times y ???

The answer is y/ (d (y^2 + d^2 )^(1/2) ) evaluated between the given limits. Can someone PLEASE tell me the error in my thinking? Thank you Frostking

2. Originally Posted by Frostking
I am in physics and my calculus skills are rusty. I need to take the integral of the following:

(d) /(y^2 + d^2)^(3/2) dy I know that I use the power rule and I end up with (y^2 + d^2)^(-1/2) / (-1/2) and then since I have the d to intergrate should that not be d times y ???

The answer is y/ (d (y^2 + d^2 )^(1/2) ) evaluated between the given limits. Can someone PLEASE tell me the error in my thinking? Thank you Frostking
I am not sure what your equation is by what you wrote.

Is this what it should look like?

$\frac{d}{(y^2+d^2)^{\frac{3}{2}}}dy$

or is it supposed to look like this?

$\frac{d}{dy}\bigg[\frac{1}{(y^2+d^2)^{\frac{3}{2}}}\bigg]$

3. ## Electrical field integral equation clarification

I am sorry that I was not clear. The first integral you put down is the correct problem. Frostking

4. Both integrals are equivalent but the 2nd one is easy for most to understand.

The answer should be $\frac{y}{d^2(\sqrt{y^2+d^2})}+C$

D is just a constant. You are integrating wrt y.