Question:

If order and degree of the differential equation corresponding to the family of curves y2 = 4a(x+a)(a is parameter) are m and n respectively, then m+n2 =

Updated On: May 4, 2026
  • 3

  • 4

  • 5

  • 2

Show Solution
collegedunia
Verified By Collegedunia

The Correct Option is C

Solution and Explanation

We are given the family of curves:

\[ y^2 = 4a(x + a) \]

1. Differentiate with respect to \( x \):

\[ 2y \frac{dy}{dx} = 4a \Rightarrow a = \frac{y}{2}\frac{dy}{dx} \]

2. Substitute \( a \) into the original equation:

\[ y^2 = 4\left(\frac{y}{2}\frac{dy}{dx}\right)\left(x + \frac{y}{2}\frac{dy}{dx}\right) \]

Simplify:

\[ y^2 = 2y\frac{dy}{dx}\left(x + \frac{y}{2}\frac{dy}{dx}\right) \]

\[ y^2 = 2xy\frac{dy}{dx} + y^2\left(\frac{dy}{dx}\right)^2 \]

Divide by \( y^2 \) (assuming \( y \neq 0 \)):

\[ 1 = \frac{2x}{y}\frac{dy}{dx} + \left(\frac{dy}{dx}\right)^2 \]

3. This is a differential equation involving \( \frac{dy}{dx} \).

Order \( m = 1 \) (highest derivative is first order).

Degree \( n = 2 \) (highest power of \( \frac{dy}{dx} \) is 2).

Thus,

\[ m + n^2 = 1 + 4 = 5 \]

Hence, the answer is \( 5 \).

Was this answer helpful?
0
2

Concepts Used:

Differential Equations

A differential equation is an equation that contains one or more functions with its derivatives. The derivatives of the function define the rate of change of a function at a point. It is mainly used in fields such as physics, engineering, biology and so on.

Orders of a Differential Equation

First Order Differential Equation

The first-order differential equation has a degree equal to 1. All the linear equations in the form of derivatives are in the first order. It has only the first derivative such as dy/dx, where x and y are the two variables and is represented as: dy/dx = f(x, y) = y’

Second-Order Differential Equation

The equation which includes second-order derivative is the second-order differential equation. It is represented as; d/dx(dy/dx) = d2y/dx2 = f”(x) = y”.

Types of Differential Equations

Differential equations can be divided into several types namely

  • Ordinary Differential Equations
  • Partial Differential Equations
  • Linear Differential Equations
  • Nonlinear differential equations
  • Homogeneous Differential Equations
  • Nonhomogeneous Differential Equations