Figure $23-59$ shows, in cross section, three infinitely large nonconducting sheets on which charge is uniformly spread. The surface charge densities are $\sigma_{1}=+2.00$
$\mu \mathrm{C} / \mathrm{m}^{2}, \sigma_{2}=+4.00 \mu \mathrm{C} / \mathrm{m}^{2}$
and $\sigma_{3}=-5.00 \mu \mathrm{C} / \mathrm{m}^{2}$, and
distance $L=1.50 \mathrm{~cm} .$ In unitvector notation, what is the net electric field at point $P$ ?