Question

What are the order and degree respectively of the differential equation $$y = x\frac{{dy}}{{dx}} + \frac{{dx}}{{dy}}\,?$$

A. $$1,\,1$$
B. $$1,\,2$$  
C. $$2,\,1$$
D. $$2,\,2$$
Answer :   $$1,\,2$$
Solution :
The given differential equation is $$y = x\frac{{dy}}{{dx}} + \frac{{dx}}{{dy}}$$
Multiplying both the sides by $$\frac{{dy}}{{dx}}$$  we get
$$\eqalign{ & \left( {\frac{{dy}}{{dx}}} \right)y = x{\left( {\frac{{dy}}{{dx}}} \right)^2} + 1 \cr & \Rightarrow x{\left( {\frac{{dy}}{{dx}}} \right)^2} - y\left( {\frac{{dy}}{{dx}}} \right) + 1 = 0 \cr} $$
Hence, order and degree of differential equation are $$1$$ and $$2.$$

Releted MCQ Question on
Calculus >> Differential Equations

Releted Question 1

A solution of the differential equation $${\left( {\frac{{dy}}{{dx}}} \right)^2} - x\frac{{dy}}{{dx}} + y = 0$$     is-

A. $$y=2$$
B. $$y=2x$$
C. $$y=2x-4$$
D. $$y = 2{x^2} - 4$$
Releted Question 2

If $${x^2} + {y^2} = 1,$$   then

A. $$yy'' - 2{\left( {y'} \right)^2} + 1 = 0$$
B. $$yy'' + {\left( {y'} \right)^2} + 1 = 0$$
C. $$yy'' + {\left( {y'} \right)^2} - 1 = 0$$
D. $$yy'' + 2{\left( {y'} \right)^2} + 1 = 0$$
Releted Question 3

If $$y\left( t \right)$$ is a solution $$\left( {1 + t} \right)\frac{{dy}}{{dt}} - ty = 1$$    and $$y\left( 0 \right) = - 1,$$   then $$y\left( 1 \right)$$ is equal to-

A. $$ - \frac{1}{2}$$
B. $$e + \frac{1}{2}$$
C. $$e - \frac{1}{2}$$
D. $$\frac{1}{2}$$
Releted Question 4

If $$y = y\left( x \right)$$   and $$\frac{{2 + \sin \,x}}{{y + 1}}\left( {\frac{{dy}}{{dx}}} \right) = - \cos \,x,\,y\left( 0 \right) = 1,$$
then $$y\left( {\frac{\pi }{2}} \right)$$   equals-

A. $$\frac{1}{3}$$
B. $$\frac{2}{3}$$
C. $$ - \frac{1}{3}$$
D. $$1$$

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Differential Equations


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