Calculating the capacitance for a cylindrical capacitor

[@KBMNVLpNdLumkstz]

brilliant explanation. thank you very much.

[@Alina-sardar123]

Thank you so much 👍👍👍 very nice

[@humanbean1452]

thanku so much!!

[@jorisbelgium]

If you integrate from a to b, this derivation is much more straightforward and much easier for students to understand. The fiddling with minus signs is not very convincing. First, you write the vector dr and then (around 7:30) you say that vector ds is in the opposite direction of vector E (which is right), but vector ds is no longer in your integral! So, why do you multiply with cos(-180°), since vectors E and dr point in the same direction??

[@Smaugthur]

I though the same, I thing you just need to multiply by minus one time.

[@claytonhouser7578]

My stupid textbook did the same thing and didn't explain it.