MCQ
The integrating factor for solving the differential equation $x \frac{d y}{d x}-y=2 x^2$ is
  • A
    $e^{-y}$
  • B
    $e^{-e}$
  • C
    $x$
  • $\frac{1}{x}$

Answer

Correct option: D.
$\frac{1}{x}$
(d) : We have, $x \frac{d y}{d x}-y=2 x^2$
i.e., $\frac{d y}{d x}-\frac{y}{x}=2 x \quad \therefore \quad$ I.F. $=e^{\int \frac{-1}{x} d x}=e^{-\ln x}=e^{\ln x^{-1}}=\frac{1}{x}$
$\therefore$ Integrating factor is $\frac{1}{x}$.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Let A and B be two events such that P(A) = 0.6, P(B) = 0.2, P(A|B) = 0.5. Then $\text{P}(\overline{\text{A}}|\overline{\text{B}})$ equals.
The matrix $\begin{bmatrix} 5 & 10 & 3 \\ -2 & -4 & 6 \\ -1 & -2 & \text{b} \end{bmatrix}$ is a singular matrix, if the value of $b$ is:
Let  ,  $f(x) = \min \left\{ {{{\sin }^{ - 1}}x,{{\cos }^{ - 1}}x} \right\}$ then area bounded by $f(x)$ and $x-$ axis is
Among :

$( S 1): \lim _{ n \rightarrow \infty} \frac{1}{ n ^2}(2+4+6+\ldots \ldots \ldots+2 n)=1$

(S2) : $\lim _{ n \rightarrow \infty} \frac{1}{ n ^{16}}\left(1^{15}+2^{15}+3^{15}+\ldots \ldots \ldots .+ n ^{15}\right)=\frac{1}{16}$

Which of the following is not a decreasing function on the interval $\left( {0,{\pi \over 2}} \right)$
If $\cot^{-1}(\sqrt{\cos\alpha})-\tan^{-1}(\sqrt{\cos\alpha})=\text{x},$ then $\sin\text{x}$ is equal to:
The corner points of the feasible region determined by the system of linear inequalities are $(0, 0), (4, 0), (2, 4)$ and $(0, 5).$ If the maximum value of $z = ax + by,$ where $a, b > 0$ occurs at both $(2, 4)$ and $(4, 0),$ then:
If $\text{A}=\displaystyle \begin{vmatrix} 1 \\ 3 \end{vmatrix}\text{B}=\displaystyle \begin{vmatrix} -1 \\ 4 \end{vmatrix}$ then $ 2\text{A}+\text{B} =$
If the function  $f(x) =  - 4{e^{\left( {\frac{{1 - x}}{2}} \right)}} + 1 + x + \frac{{{x^2}}}{2} + \frac{{{x^3}}}{3}$ and $g(x)=f^{-1}(x) \,;$ then the value of $g'(-\frac{7}{6})$ equals
For a real number $x$ let $[x]$ denote the largest integer less than or equal to $x$. The smallest positive integer $n$ for which the integral $\int \limits_1^n[x][\sqrt{x}] d x$ exceeds $60$ is