For the given equation, form a differential equation representing the given family of curves by eliminating arbitrary constants a and b.
y=e2x(a+bx)
Given, y=e2x(a+bx) ....(i)
On differentiating both sides w.r.t. x, we get
dydx=e2xddx(a+bx)+(a+bx)ddxe2x (using product rule of differentiation)
⇒dydx=e2x(b)+2e2x(a+bx)⇒y′=2y+be2x ....(ii)
Again differentiating Eq. (ii) w.r.t. x, we get
y′′=2y′+2be2x ....(iii)
On multiplying Eq.(ii) by 2 and then substracting from Eq. (iii), we get
y′′=2y′+2(y′−2y)⇒y′′=2y′+2y′−4y⇒y′′−4y′+4y=0
which is the required differential equation.