Which expression describes the separation of variables for dydx=exy2\frac{dy}{dx} = \frac{e^x}{y^2}dxdy=y2ex?
y2dy=exdxy^2 dy = e^x dxy2dy=exdx
exdy=y2dxe^x dy = y^2 dxexdy=y2dx
1y2dy=exdx\frac{1}{y^2} dy = e^x dxy21dy=exdx
y2dx=exdyy^2 dx = e^x dyy2dx=exdy