Question
The integrating factor of $\frac{{xdy}}{{dx}} - y = {x^4} - 3x$ is
- (a) $x$
- (b) $\log x$
- (c) $\frac{1}{x}$ ✓ Correct
- (d) $- x$
The integrating factor of $\frac{{xdy}}{{dx}} - y = {x^4} - 3x$ is
Given that, $x\frac{{dy}}{{dx}} - y = {x^4} - 3x$
$\Rightarrow$ $\frac{{dy}}{{dx}} - \frac{y}{x} = {x^3} - 3$
Here, $P = - \frac{1}{x},Q = {x^3} - 3$
$\therefore \mid$ $IF = {e^{\int P dx}} = {e^{ - \int {\frac{1}{x}} dx}} = {e^{ - \log x}}$
$= \frac{1}{x}$
NCERT & Exemplar solution for CBSE Class 12 Mathematics, Differential Equations. Curated by Sachin Sharma. Free for all students.