Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Differential Equations

Question:

The solution of the differential equation dy/dx + (y/x) = x is-

Options:

xy = x3/3+ C

xy = x4/5+ C

xy = x4/6+ C

xy = x4/4+ C

Correct Answer:

xy = x3/3+ C

Explanation:

The given differential equation is dy/dx + (y/x) = x 

This ifs of the form dy/dx +Py = Q

where P = 1/x, Q= x

I.F. = e∫Pdx = e∫(1/x) dx =elogx = x

The solution of the given differential equation is given by-

y(I.F.) = ∫(Q x I.F.)dx + C

⇒yx = ∫(x.x.)dx + C 

⇒ yx = ∫(x2)dx + C 

⇒xy= x3/3+ C