Figure $29-50 a$ shows, in cross section, two long, parallel wires carrying current and separated by distance $L .$ The ratio $i_{1} / i_{2}$
of their currents is $4.00 ;$ the directions of the currents are not indicated. Figure $29-50 b$ shows the $y$ component $B_{y}$ of their net magnetic field along the $x$ axis to the right of wire $2 .$ The vertical scale is set by $B_{y s}=4.0 \mathrm{nT}$ , and the horizontal scale is set by $x_{s}=20.0 \mathrm{cm}$ .
(a) At what value of $x>0$ is $B_{v}$ maximum? (b) If $i_{2}=3 \mathrm{mA}$ , what is the value of that maximum? What is the direction (into or out of the
page $)$ of $(\mathrm{c}) i_{1}$ and $(\mathrm{d}) i_{2}$ ?