In the figure what is the net electric potential at the origin due to the circular arc of charge $Q_1=+9\mathrm{.}00pC$ and the two particles of

charges $Q_2=3\mathrm{.}30Q_1$ and $Q_3=-2\mathrm{.}40Q_1?$ The arc's center of curvature is at the origin and its radius is $R=3\mathrm{.}10m$; the angle indicated is $$

$=21\mathrm{.}0.$