Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Differential Equations

Question:

The solution of the differential equation dy/dx + 4y = e-10x is-

Options:

y= -e-10x /6+ Ce4x 

y= -e-10x /10+ Ce-4x 

y= -e-10x /6+ Ce-4x 

y= e-10x /6+ Ce-4x 

Correct Answer:

y= -e-10x /6+ Ce-4x 

Explanation:

The given differential equation is dy/dx + 4y = e-10x

which is of the form dy/dx + py =Q   (Where p= 4 and Q=e-10x )

Now, I.F. = e∫pdx

I.F. = e∫4dx 

So. I.F. = e4x

The solution is given by:

y.(I.F.) = ∫Q x(I.F.)dx +C

⇒ y.e4x =  ∫(e-10x x e4x) dx +C

so. y= -e-10x /6+ Ce-4x