Which of the following equations represent Biot-savart law ?
dB = `(mu_@)/(4pi)``(I dl)/(r^2)`
dB = `(mu_@)/(4pi)``(I. dl sin theta)/(r^2)`
Both dB = `(mu_o)/(4pi)`.`(I.dl sin theta)/(r^2)` and `vec(dB)` = `(mu_o)/(4pi)` `(vec(Idl)xxvecr)/r^3`
`vec(dB)` = `(mu_@)/(4pi)``(I vec(dl) xx vecr)/(r^3)`