# Thread: integral mathematical part of physics question..

1. ## integral mathematical part of physics question..

i got a ring a small part of that ring is dq
then the whole ring is q

but i cant get this result in the integral
$
\int_{0}^{2\pi}dq=2\pi-0=2\pi
$

i should get the result "q"

2. ## Definite

This is a definite integral. In general, $\int dx=x+C$, so $\int_0^{2\pi}dq=q|_0^{2\pi}=2\pi-0=2\pi$