English

Show that the given differential equation is homogeneous and solve them. (x2 – y2) dx + 2xy dy = 0 - Mathematics

Advertisements
Advertisements

Question

Show that the given differential equation is homogeneous and solve them.

(x2 – y2) dx + 2xy dy = 0

Sum

Solution

(x2 - y2) dx + 2xy dy = 0

Which can be written as

`dy/dx = (y^2 - x^2)/(2 xy)`

`= ((y/x)^2 - 1)/(2 (y/x))`                 ....(1)

Since R.H.S is of the form `g(y/x)`, and so it is a homogeneous function of degree zero

Therefore equation (1) is a homogeneous differential equation.

⇒ `dy/dx = v + x (dv)/dx`, then (1) become

`v + x (dv)/dx = (v^2 - 1)/(2v)`

⇒ `x (dv)/dx = (v^2 - 1)/(2v) - v`

⇒ `(2vdv)/(v^2 + 1) = -dx/x`                 ....(2)

Integrating (2) both sides, we get

log |v2 + 1| = - log |x| + C

⇒ log |(v2 + 1) x | = C

⇒ `log |(y^2 + x^2)/x| = C_1`                 ...`(∵ v = y/x)`

⇒ `|(y^2 + x^2)/x| = e^(C_(1))`

⇒ `(x^2 + y^2)/x =pm  e^(C_(1)) = C`    (say)

⇒ `x^2 + y^2 = Cx`

which is the required general solution of the given differential equation.

shaalaa.com
  Is there an error in this question or solution?
Chapter 9: Differential Equations - Exercise 9.5 [Page 406]

APPEARS IN

NCERT Mathematics [English] Class 12
Chapter 9 Differential Equations
Exercise 9.5 | Q 4 | Page 406

RELATED QUESTIONS

Show that the differential equation 2yx/y dx + (y − 2x ex/y) dy = 0 is homogeneous. Find the particular solution of this differential equation, given that x = 0 when y = 1.


 

Show that the differential  equation `2xydy/dx=x^2+3y^2`  is homogeneous and solve it.

 

Find the particular solution of the differential equation:

2y ex/y dx + (y - 2x ex/y) dy = 0 given that x = 0 when y = 1.


Show that the given differential equation is homogeneous and solve them.

(x2 + xy) dy = (x2 + y2) dx


Show that the given differential equation is homogeneous and solve them.

`x^2 dy/dx = x^2 - 2y^2 + xy`


Show that the given differential equation is homogeneous and solve them.

`{xcos(y/x) + ysin(y/x)}ydx = {ysin (y/x) -  xcos(y/x)}xdy`


Show that the given differential equation is homogeneous and solve them.

`x dy/dx - y +  x sin (y/x) = 0`


For the differential equation find a particular solution satisfying the given condition:

`dy/dx -  y/x + cosec (y/x) = 0; y = 0` when x = 1


A homogeneous differential equation of the from `dx/dy = h (x/y)` can be solved by making the substitution.


Which of the following is a homogeneous differential equation?


Find the particular solution of the differential equation `(x - y) dy/dx = (x + 2y)` given that y = 0 when x = 1.


\[\frac{y}{x}\cos\left( \frac{y}{x} \right) dx - \left\{ \frac{x}{y}\sin\left( \frac{y}{x} \right) + \cos\left( \frac{y}{x} \right) \right\} dy = 0\]

\[\left( 1 + e^{x/y} \right) dx + e^{x/y} \left( 1 - \frac{x}{y} \right) dy = 0\]

\[\left( x^2 + y^2 \right)\frac{dy}{dx} = 8 x^2 - 3xy + 2 y^2\]

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

\[x\frac{dy}{dx} - y = 2\sqrt{y^2 - x^2}\]

\[y dx + \left\{ x \log\left( \frac{y}{x} \right) \right\} dy - 2x dy = 0\]

Solve the following initial value problem:
 (x2 + y2) dx = 2xy dy, y (1) = 0


Solve the following initial value problem:
\[x e^{y/x} - y + x\frac{dy}{dx} = 0, y\left( e \right) = 0\]


Solve the following initial value problem:
(xy − y2) dx − x2 dy = 0, y(1) = 1


Solve the following initial value problem:
(y4 − 2x3 y) dx + (x4 − 2xy3) dy = 0, y (1) = 1


Solve the following initial value problem:
\[\left\{ x \sin^2 \left( \frac{y}{x} \right) - y \right\}dx + x dy = 0, y\left( 1 \right) = \frac{\pi}{4}\]


Which of the following is a homogeneous differential equation?


Solve the following differential equation : \[\left[ y - x  \cos\left( \frac{y}{x} \right) \right]dy + \left[ y  \cos\left( \frac{y}{x} \right) - 2x  \sin\left( \frac{y}{x} \right) \right]dx = 0\] .


Solve the differential equation: x dy - y dx = `sqrt(x^2 + y^2)dx,` given that y = 0 when x = 1.


Solve the following differential equation:

y2 dx + (xy + x2)dy = 0


Solve the following differential equation:

`(1 + "e"^("x"/"y"))"dx" + "e"^("x"/"y")(1 - "x"/"y")"dy" = 0`


Solve the following differential equation:

x dx + 2y dx = 0, when x = 2, y = 1


Solve the following differential equation:

(x2 + 3xy + y2)dx - x2 dy = 0


Solve the following differential equation:

(x2 – y2)dx + 2xy dy = 0


Solcve: `x ("d"y)/("d"x) = y(log y – log x + 1)`


A homogeneous differential equation of the `(dx)/(dy) = h(x/y)` can be solved by making the substitution.


Let the solution curve of the differential equation `x (dy)/(dx) - y = sqrt(y^2 + 16x^2)`, y(1) = 3 be y = y(x). Then y(2) is equal to ______.


If a curve y = f(x), passing through the point (1, 2), is the solution of the differential equation, 2x2dy = (2xy + y2)dx, then `f(1/2)` is equal to ______.


Find the general solution of the differential equation:

(xy – x2) dy = y2 dx


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×