Figure $29-85$ shows, in cross section, two long parallel wires that are
separated by distance $d=18.6 \mathrm{cm} .$
Each carries $4.23 \mathrm{A},$ out of the page
in wire 1 and into the page in wire $2 .$
In unit-vector notation, what is the
net magnetic field at point $P$ at distance $R=34.2 \mathrm{cm},$ due to the two
currents?