Form the differential equation of the family of curves y\;=\;ae^{bx}, where a and b are arbitrary constants.
Form the differential equation of the family of curves y\;=\;ae^{bx}, where a and b are arbitrary constants.

Equation of the family of curves, y=a e^{b x}, where a and b are arbitrary constants.
Differentiating the above equation with respect to x on both sides, we have,
\begin{array}{l} y=a e^{b x}(1) \\ \frac{d y}{d x}=a b e^{b x}(2) \\ \frac{d^{2} y}{d x^{2}}=a b^{2} e^{b x} \end{array}
y \frac{d^{2} y}{d x^{2}}=a b^{2} e^{b x}\left(a e^{b x}\right) (Multiplying both sides of the equation by y )
y \frac{d^{2} y}{d x^{2}}=\left(a b e^{b x}\right)^{2} (Substituting equation 2 in this equation)
y \frac{d^{2} y}{d x^{2}}=\left(\frac{d y}{d x}\right)^{2}
This is the required differential equation.