English

D Y D X = 2 X Y , Y ( 0 ) = 1

Advertisements
Advertisements

Question

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

Solution

\[ \frac{dy}{dx} = 2xy, y\left( 0 \right) = 1\]
\[ \Rightarrow \frac{1}{y}dy = 2x dx\]
Integrating both sides, we get 
\[\int\frac{1}{y}dy = \int2x dx\]
\[\log \left| y \right| = x^2 + C . . . . . (1)\]
\[\text{We know that at }x = 0, y = 1 . \]
Substituting the values of x and y in (1), we get
\[0 = 0 + C\]
\[ \Rightarrow C = 0\]
Substituting the value of C in (1), we get 
\[\log \left| y \right| = x^2 \]
\[ \Rightarrow y = e^{x^2} \]
\[\text{ Hence, }y = e^{x^2}\text{ is the required solution }. \]

shaalaa.com
  Is there an error in this question or solution?
Chapter 21: Differential Equations - Exercise 22.07 [Page 56]

APPEARS IN

R.D. Sharma Mathematics Volume 1 and 2 [English] Class 12
Chapter 21 Differential Equations
Exercise 22.07 | Q 45.5 | Page 56

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`


\[y\frac{d^2 x}{d y^2} = y^2 + 1\]

Show that the differential equation of which y = 2(x2 − 1) + \[c e^{- x^2}\] is a solution, is \[\frac{dy}{dx} + 2xy = 4 x^3\]


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


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


Verify that y2 = 4a (x + a) is a solution of the differential equations
\[y\left\{ 1 - \left( \frac{dy}{dx} \right)^2 \right\} = 2x\frac{dy}{dx}\]


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

\[\cos x\frac{dy}{dx} - \cos 2x = \cos 3x\]

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

\[\frac{dy}{dx} = \sin^2 y\]

\[\left( x - 1 \right)\frac{dy}{dx} = 2 xy\]

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

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


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

Find the particular solution of edy/dx = x + 1, given that y = 3, when x = 0.


Find the solution of the differential equation cos y dy + cos x sin y dx = 0 given that y = \[\frac{\pi}{2}\], when x = \[\frac{\pi}{2}\] 

 


In a culture the bacteria count is 100000. The number is increased by 10% in 2 hours. In how many hours will the count reach 200000, if the rate of growth of bacteria is proportional to the number present.


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

Solve the following initial value problem:-

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


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


In a simple circuit of resistance R, self inductance L and voltage E, the current `i` at any time `t` is given by L \[\frac{di}{dt}\]+ R i = E. If E is constant and initially no current passes through the circuit, prove that \[i = \frac{E}{R}\left\{ 1 - e^{- \left( R/L \right)t} \right\}.\]


Find the curve for which the intercept cut-off by a tangent on x-axis is equal to four times the ordinate of the point of contact.

 

The x-intercept of the tangent line to a curve is equal to the ordinate of the point of contact. Find the particular curve through the point (1, 1).


If sin x is an integrating factor of the differential equation \[\frac{dy}{dx} + Py = Q\], then write the value of P.


The differential equation \[x\frac{dy}{dx} - y = x^2\], has the general solution


Integrating factor of the differential equation cos \[x\frac{dy}{dx} + y \sin x = 1\], is


If xmyn = (x + y)m+n, prove that \[\frac{dy}{dx} = \frac{y}{x} .\]


Solve the following differential equation.

`y^3 - dy/dx = x dy/dx`


`xy dy/dx  = x^2 + 2y^2`


Solve the differential equation `("d"y)/("d"x) + y` = e−x 


Solve the differential equation xdx + 2ydy = 0


Solve the following differential equation `("d"y)/("d"x)` = x2y + y


Choose the correct alternative:

General solution of `y - x ("d"y)/("d"x)` = 0 is


The function y = ex is solution  ______ of differential equation


Solve the following differential equation

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


Integrating factor of the differential equation `x "dy"/"dx" - y` = sinx is ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×