The discussion revolves around finding an expression for the electric potential at the center of a semicircular rod with charge Q and radius R. The original poster attempts to derive the potential using integration but encounters a discrepancy in their result.
Some participants have offered guidance on the integration approach, suggesting the need to use dθ instead of dx for polar coordinates. The conversation reflects a productive exploration of the problem, with participants questioning assumptions and clarifying the integration method.
There is a mention of the arbitrary nature of the starting angle for the semicircle, indicating that different approaches to setting limits may yield similar results. The original poster's confusion about the cancellation of terms in their expression is also noted.
Your integrand has a dx in it. What did you do with it? To integrate over an angle you need a dθ in the integrand.PolarBee said:I integrated from pi/2 to 3pi/2. Which came out to be just pi and that canceled out the pi from L = pi * r.