हिंदी

Solve the differential equation (x2 + y2)dx- 2xydy = 0

Advertisements
Advertisements

प्रश्न

Solve the differential equation (x2 + y2)dx- 2xydy = 0

योग
Advertisements

उत्तर

(x2 + y2)dx- 2xydy = 0

(x2 + y2) dx = 2xydy

`dy/dx = (x^2 + y^2)/(2xy)`.........(i)

The equation is a homogeneous equation
Let y= vx,
Differentiat ing w.r.t. x, we get,

`dy/dx=v+x(dv)/dx`

`dy/dx=(x^2+y^2)/(2xy) " from "(i)`

`v+x(dv)/dx=(x^2+(vx)^2)/(2x.(vx))`

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

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

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

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

`(2v)/(1-v^2)dv=1/xdx`.......(ii)

Which is in variables separatable form

∴ Integrating both sides, we get

`int(2v)/(1-v^2)dv=int1/xdx + c_1`

`therefore -log|1-v^2|=log|x|+logc`

`therefore log|x(1-v^2)|=log|c|`

`therefore x(1-v^2)=c`

Resubstituting `v=y/x` we get

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

`x((x^2-y^2)/x^2)=c `

`therefore x^2 - y^2 = cx`, where c is constant

which is the required general solution

shaalaa.com
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
2014-2015 (March)

APPEARS IN

संबंधित प्रश्न

Solve the differential equation :

`y+x dy/dx=x−y dy/dx`


 

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

 

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

`x  dy - y  dx =  sqrt(x^2 + y^2)   dx`


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

`x dy/dx - y +  x sin (y/x) = 0`


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

`y  dx + x log(y/x)dy - 2x  dy = 0`


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

x2 dy + (xy + y2) dx = 0; y = 1 when x = 1


Which of the following is a homogeneous differential equation?


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

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

(x2 − 2xy) dy + (x2 − 3xy + 2y2) dx = 0


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

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

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

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

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

 


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


Find the particular solution of the differential equation \[\left( x - y \right)\frac{dy}{dx} = x + 2y\], given that when x = 1, y = 0.


Show that the family of curves for which \[\frac{dy}{dx} = \frac{x^2 + y^2}{2xy}\], is given by \[x^2 - y^2 = Cx\]


Solve the following differential equation:

`(1 + 2"e"^("x"/"y")) + 2"e"^("x"/"y")(1 - "x"/"y") "dy"/"dx" = 0`


Solve the following differential equation:

`x^2.  dy/dx = x^2 + xy + y^2`


Solve the following differential equation:

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


Find the equation of a curve passing through `(1, pi/4)` if the slope of the tangent to the curve at any point P(x, y) is `y/x - cos^2  y/x`.


Which of the following is not a homogeneous function of x and y.


The solution of the differential equation `(1 + e^(x/y)) dx + e^(x/y) (1 + x/y) dy` = 0 is


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 ______.


The differential equation y' = `y/(x + sqrt(xy))` has general solution given by:

(where C is a constant of integration)


What replacement obtains the final answer after using a homogeneous substitution?


For \[F(x,y)=\frac{y\cos\left(\frac{y}{x}\right)+x}{x\cos\left(\frac{y}{x}\right)}\], what is \[F(\lambda x,\lambda y)\]?


After putting \[y=vx\] in \[\frac{dy}{dx}=\frac{y\cos\left(\frac{y}{x}\right)+x}{x\cos\left(\frac{y}{x}\right)}\], which equation results?


Which sequence correctly states the essential actions for obtaining the final answer of a homogeneous differential equation?


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×