English

Solve: dydx+2xy = x2

Advertisements
Advertisements

Question

Solve: `("d"y)/("d"x) + 2/xy` = x2 

Sum
Advertisements

Solution

`("d"y)/("d"x) + 2/xy` = x2 

The given equation is of the form

`("d"y)/("d"x) + "P"y` = Q.

where P = `2/x` and Q = x2

∴ I.F. = `"e"^(int^("Pd"x))`

= `"e"^(int2/x)  "d"x`

= `"e"^(2logx)`

= `"e"^(log x^2)`

= x2

∴ Solution of the given equation is

`y("I"."F".) = int"Q"("I.""F.")  "d"x + "c"_1`

∴ `y * x^2 = intx^2 * x^2  "d"x + "c"_1`

∴ `yx^2 = intx^4  "d"x + "c"_1`

∴ yx2 = `x^5/5 + "c"_1`

∴ 5x2y = x5 + c, where c = 5c1 

shaalaa.com
  Is there an error in this question or solution?
Chapter 1.8: Differential Equation and Applications - Q.4

RELATED QUESTIONS

Prove that:

`int_0^(2a)f(x)dx = int_0^af(x)dx + int_0^af(2a - x)dx`


If 1, `omega` and `omega^2` are the cube roots of unity, prove `(a + b omega + c omega^2)/(c + s omega +  b omega^2) =  omega^2`


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

\[\sqrt{1 + \left( \frac{dy}{dx} \right)^2} = \left( c\frac{d^2 y}{d x^2} \right)^{1/3}\]

\[\sqrt[3]{\frac{d^2 y}{d x^2}} = \sqrt{\frac{dy}{dx}}\]

Form the differential equation of the family of hyperbolas having foci on x-axis and centre at the origin.


Show that the function y = A cos 2x − B sin 2x is a solution of the differential equation \[\frac{d^2 y}{d x^2} + 4y = 0\].


Show that y = AeBx is a solution of the differential equation

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

Show that y = ax3 + bx2 + c is a solution of the differential equation \[\frac{d^3 y}{d x^3} = 6a\].

 


For the following differential equation verify that the accompanying function is a solution:

Differential equation Function
\[x + y\frac{dy}{dx} = 0\]
\[y = \pm \sqrt{a^2 - x^2}\]

For the following differential equation verify that the accompanying function is a solution:

Differential equation Function
\[x^3 \frac{d^2 y}{d x^2} = 1\]
\[y = ax + b + \frac{1}{2x}\]

Differential equation \[x\frac{dy}{dx} = 1, y\left( 1 \right) = 0\]

Function y = log x


Differential equation \[\frac{dy}{dx} = y, y\left( 0 \right) = 1\]
Function y = ex


Differential equation \[\frac{d^2 y}{d x^2} - \frac{dy}{dx} = 0, y \left( 0 \right) = 2, y'\left( 0 \right) = 1\]

Function y = ex + 1


Differential equation \[\frac{dy}{dx} + y = 2, y \left( 0 \right) = 3\] Function y = e−x + 2


Differential equation \[\frac{d^2 y}{d x^2} - y = 0, y \left( 0 \right) = 2, y' \left( 0 \right) = 0\] Function y = ex + e−x


\[\frac{dy}{dx} = \log x\]

\[\frac{dy}{dx} - x \sin^2 x = \frac{1}{x \log x}\]

\[\frac{dy}{dx} = x^5 \tan^{- 1} \left( x^3 \right)\]

\[\sin^4 x\frac{dy}{dx} = \cos x\]

\[\sqrt{1 - x^4} dy = x\ dx\]

\[\frac{dy}{dx} = x e^x - \frac{5}{2} + \cos^2 x\]

\[\frac{dy}{dx} + \frac{1 + y^2}{y} = 0\]

\[\frac{dy}{dx} = \frac{1 + y^2}{y^3}\]

\[\frac{dy}{dx} = \frac{1 - \cos 2y}{1 + \cos 2y}\]

Solve the differential equation \[\frac{dy}{dx} = e^{x + y} + x^2 e^y\].

\[\sqrt{1 + x^2 + y^2 + x^2 y^2} + xy\frac{dy}{dx} = 0\]

tan y \[\frac{dy}{dx}\] = sin (x + y) + sin (x − y) 

 


\[\frac{dy}{dx} = e^{x + y} + e^{- x + y}\]

Solve the following differential equation: 
(xy2 + 2x) dx + (x2 y + 2y) dy = 0


Solve the following differential equation:
\[xy\frac{dy}{dx} = 1 + x + y + xy\]

 


Solve the following differential equation:
\[y\left( 1 - x^2 \right)\frac{dy}{dx} = x\left( 1 + y^2 \right)\]

 


Solve the following differential equation:
\[\left( 1 + y^2 \right) \tan^{- 1} xdx + 2y\left( 1 + x^2 \right)dy = 0\]


\[xy\frac{dy}{dx} = y + 2, y\left( 2 \right) = 0\]

\[\frac{dy}{dx} = y \sin 2x, y\left( 0 \right) = 1\]

\[2x\frac{dy}{dx} = 5y, y\left( 1 \right) = 1\]

\[\frac{dy}{dx} = 1 + x + y^2 + x y^2\] when y = 0, x = 0

Solve the differential equation \[x\frac{dy}{dx} + \cot y = 0\] given that \[y = \frac{\pi}{4}\], when \[x=\sqrt{2}\]


Solve the differential equation \[\left( 1 + x^2 \right)\frac{dy}{dx} + \left( 1 + y^2 \right) = 0\], given that y = 1, when x = 0.


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

\[2xy\frac{dy}{dx} = x^2 + y^2\]

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

3x2 dy = (3xy + y2) dx


\[\left[ x\sqrt{x^2 + y^2} - y^2 \right] dx + xy\ dy = 0\]

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


A population grows at the rate of 5% per year. How long does it take for the population to double?


If the interest is compounded continuously at 6% per annum, how much worth Rs 1000 will be after 10 years? How long will it take to double Rs 1000?


Show that the equation of the curve whose slope at any point is equal to y + 2x and which passes through the origin is y + 2 (x + 1) = 2e2x.


Find the equation of the curve such that the portion of the x-axis cut off between the origin and the tangent at a point is twice the abscissa and which passes through the point (1, 2).


Show that all curves for which the slope at any point (x, y) on it is \[\frac{x^2 + y^2}{2xy}\]  are rectangular hyperbola.


The differential equation obtained on eliminating A and B from y = A cos ωt + B sin ωt, is


Which of the following is the integrating factor of (x log x) \[\frac{dy}{dx} + y\] = 2 log x?


Solve the differential equation:

`"x"("dy")/("dx")+"y"=3"x"^2-2`


Solve the following differential equation.

x2y dx − (x3 + y3) dy = 0


Solve the following differential equation.

`dy/dx + y = e ^-x`


The differential equation of `y = k_1e^x+ k_2 e^-x` is ______.


State whether the following is True or False:

The degree of a differential equation is the power of the highest ordered derivative when all the derivatives are made free from negative and/or fractional indices if any.


y2 dx + (xy + x2)dy = 0


`xy dy/dx  = x^2 + 2y^2`


Solve the differential equation sec2y tan x dy + sec2x tan y dx = 0


Solve the differential equation xdx + 2ydy = 0


For the differential equation, find the particular solution (x – y2x) dx – (y + x2y) dy = 0 when x = 2, y = 0


For the differential equation, find the particular solution

`("d"y)/("d"x)` = (4x +y + 1), when y = 1, x = 0


Choose the correct alternative:

Differential equation of the function c + 4yx = 0 is


The solution of differential equation `x^2 ("d"^2y)/("d"x^2)` = 1 is ______


Verify y = log x + c is the solution of differential equation `x ("d"^2y)/("d"x^2) + ("d"y)/("d"x)` = 0


Solve the following differential equation

`y log y ("d"x)/("d"y) + x` = log y


Given that `"dy"/"dx"` = yex and x = 0, y = e. Find the value of y when x = 1.


The integrating factor of the differential equation `"dy"/"dx" (x log x) + y` = 2logx is ______.


Solve the differential equation `"dy"/"dx" + 2xy` = y


Solve the differential equation `"dy"/"dx"` = 1 + x + y2 + xy2, when y = 0, x = 0.


A man is moving away from a tower 41.6 m high at a rate of 2 m/s. If the eye level of the man is 1.6 m above the ground, then the rate at which the angle of elevation of the top of the tower changes, when he is at a distance of 30 m from the foot of the tower, is


The value of `dy/dx` if y = |x – 1| + |x – 4| at x = 3 is ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×