1. The problem statement, all variables and given/known data Find the Electric field a distance z above one end of a straight line segment of length L that carries a uniform line charge λ 2. Relevant equations Complicated formula due to lack of font for the notation used by the author of the book. so I wrote it out. I did my best to differentiate between the script r and pi. just in case I did a terrible job, only the first "r" is pi, the rest are script r's 3. The attempt at a solution My professor says during the lecture while doing this problem that the λ is not dependent on r so is a constant and can be pulled out of the integral, but then it also just disappears from the problem completely. Why?