dydx=aPeax+bQebx⟶eq.1⇒−(a+b)dydx=(−a−b)(aPeax+bQebx)⇒−a2Peax−abQebx−abPeax−b2Qebx⟶eq.2⇒aby=abQebx+abPeax⟶eq.3
Adding equation 1,2,3
d2ydx2−(a+b)dydx+aby=a2Peax+b2Qebx−a2Peax−abQebx⇒abPeax−b2Qebx+abPeax+abQebx⇒d2ydx2−(a+b)dydx+aby=0
If y=Peax+Qebx, then prove that d2ydx2−(a+b)dydx+aby=0