Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Differential Equations

Question:

Match the Integrating factor of the following Differential equations.

LIST I

LIST II

 A. $\frac{d y}{d x}-y=\cos x$ 

 I. $e^x$ 

 B. $\frac{d y}{d x}=\cos x-y$ 

 II. $x^2$ 

 C. $x \frac{d y}{d x}+2 y=x^2$ 

 III. $\frac{1}{x^2}$ 

 D. $\frac{d y}{d x}=x+\frac{2}{x} y$ 

 IV. $e^{-x}$ 

Choose the correct answer from the options given below:

Options:

A-IV, B-I, C-II, D-III

A-II, B-III, C-IV, D-I

A-III, B-IV, C-I, D-II

A-III, B-I, C-IV, D-II

Correct Answer:

A-IV, B-I, C-II, D-III

Explanation:

The correct answer is Option (1) → A-IV, B-I, C-II, D-III

(A) $\frac{d y}{d x}-y=\cos x⇒I.F.=e^{-1dx}=e^{-x}$ (IV)

(B) $\frac{dy}{dx}+y=\cos x⇒I.F.=e^{1dx}=e^{x}$ (I)

(C) $\frac{dy}{dx}+\frac{2}{x}y=x⇒I.F.=e^{\frac{2}{x}dx}=e^{\log x^2}=x^2$ (II)

(D) $\frac{dy}{dx}-\frac{2}{x}y=x⇒I.F.=e^{-\frac{2}{x}dx}=e^{\log \frac{1}{x^2}}=\frac{1}{x^2}$ (III)