how to write the expression ((pi*epsil​on)/ln((D-​r)/r)) in matlab?

c = (pi*epsilon)/log((D-r)/r);

This code doesn't work

[KSSV]

Why it didn't work? What did you try? Show us your code..

[Walter Roberson]

The code could fail in some cases involving non-scalars, as the A/B operator is sort of like A*pinv(B) except with some size restrictions. The element-by-element division operator is ./ not /

Answer 1

[David Hill]

Are all the variables arrays of equal size? If so, then you need the element-wise operator.

c = (pi*epsilon)./log((D-r)./r);