Moving Charges And Magnetism

$\frac{\mu_0 I}{4 \pi r}+\frac{\mu_0 I}{r}$

$\frac{\mu_0 I}{4 \pi r}+\frac{\mu_0 I}{2 r}$

$\frac{\mu_0 \mathrm{I}}{4 \pi \mathrm{r}}+\frac{\mu_0 \mathrm{I}}{4 \mathrm{r}}$

$\frac{\mu_0 \mathrm{I}}{4 \pi \mathrm{r}}-\frac{\mu_0 \mathrm{I}}{4 \mathrm{r}}$