Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Differential Equations

Question:

Match List-I with List-II

List-I

List-II

(A) Degree of this differential equation $\frac{d^4y}{dx^4}+2\log_e(\frac{d^3y}{dx^3})=0$

(I) 1

(B) Order of this differential equation $e^{(\frac{dy}{dx})^3}+3y(\frac{d^2y}{dx^2})^3=0$

(II) 4

(C) Degree of $\frac{d^4y}{dx^4}+(\frac{dy}{dx})^2= 0$

(III) not defined

(D) Order of the differential equation $2\frac{d^4y}{dx^4}+(\frac{d^2y}{dx^2})^5=0$

(IV) 2

Choose the correct answer from the options given below:

Options:

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

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

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

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

Correct Answer:

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

Explanation:

The correct answer is Option (2) → (A)-(III), (B)-(IV), (C)-(I), (D)-(II)

List-I

List-II

(A) Degree of this differential equation $\frac{d^4y}{dx^4}+2\log_e(\frac{d^3y}{dx^3})=0$

(III) not defined

(B) Order of this differential equation $e^{(\frac{dy}{dx})^3}+3y(\frac{d^2y}{dx^2})^3=0$

(IV) 2

(C) Degree of $\frac{d^4y}{dx^4}+(\frac{dy}{dx})^2= 0$

(I) 1

(D) Order of the differential equation $2\frac{d^4y}{dx^4}+(\frac{d^2y}{dx^2})^5=0$

(II) 4

$\text{(A) } \frac{d^{4}y}{dx^{4}}+2\log\!\left(\frac{d^{3}y}{dx^{3}}\right)=0$

$\text{Contains }\log\!\left(\frac{d^{3}y}{dx^{3}}\right)\Rightarrow\text{not a polynomial in derivatives}\Rightarrow\text{degree not defined}$

$\Rightarrow\ \text{(A)}\to\text{(III) not defined}$

$\text{(B) } e^{\left(\frac{dy}{dx}\right)^{3}}+3y\left(\frac{d^{2}y}{dx^{2}}\right)^{3}=0$

$\text{Highest-order derivative is } \frac{d^{2}y}{dx^{2}}\Rightarrow \text{order}=2$

$\Rightarrow\ \text{(B)}\to\text{(IV) }2$

$\text{(C) } \frac{d^{4}y}{dx^{4}}+\left(\frac{dy}{dx}\right)^{2}=0$

$\text{Polynomial in derivatives; highest-order term } \frac{d^{4}y}{dx^{4}}\text{ has power }1\Rightarrow\text{degree}=1$

$\Rightarrow\ \text{(C)}\to\text{(I) }1$

$\text{(D) } 2\frac{d^{4}y}{dx^{4}}+\left(\frac{d^{2}y}{dx^{2}}\right)^{5}=0$

$\text{Highest-order derivative } \frac{d^{4}y}{dx^{4}}\Rightarrow \text{order}=4$

$\Rightarrow\ \text{(D)}\to\text{(II) }4$

Matching: (A)→(III), (B)→(IV), (C)→(I), (D)→(II)