For the following question verify that the given function (implicit or explicit) is a solution of the corresponding differential equation.
y=ex(acosx+bsinx):d2ydx2−2dydx+2y=0
Given, y=ex(acosx+bsinx)
On dividing by ex both sides, we get
e−xy=acosx+bsinx) ...(i)
On differentiating both sides w.r.t. x, we get
e−xdydx−ye−x=−asinx+bcosx
Again, differentiating both sides with respect to x, we get
e−xd2ydx2−dydxe−x−{−ye−x+e−xdydx}=−acosx−bsinx⇒e−xd2ydx2−dydxe−x+ye−x−e−xdydx=−(acosx+bsinx)⇒e−xd2ydx2−2e−xdydx+ye−x=−ye−x [From Eq. (i)]
⇒e−xd2ydx2−2e−xdydx+2ye−x=0⇒e−x{d2ydx62−2dydx+2y}=0⇒d2ydx2−2dydx+2y=0
Hence, the given function is a solution of the corresponding differential equation.