y'(x) \left(\frac{\text{e1} (a+x)}{\left((a+x)^2+y(x)^2\right)^{3/2}}+\frac{\text{e2} (x-a)}{\left((x-a)^2+y(x)^2\right)^{3/2}}\right)-y(x) \left(\frac{\text{e1}}{\left((a+x)^2+y(x)^2\right)^{3/2}}+\frac{\text{e2}}{\left((x-a)^2+y(x)^2\right)^{3/2}}\right)=0