Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Differential Equations

Question:

On putting $\frac{y}{x}=v$ the differential equation $\frac{d y}{d x}=\frac{2 x y-y^2}{2 x y-x^2}$ is transformed to

Options:

$x(2 v-1) d x=3 v(v-1) d x$

$x(2 v-1) d v=3 v(1-v) d x$

$x(1-2 v) d v=\left(v^2-2 v\right) d x$

$x(1-2 v) d v=\left(v^2-2 v\right) d x$

Correct Answer:

$x(2 v-1) d v=3 v(1-v) d x$

Explanation:

Putting $y=v x$ and $\frac{d y}{d x}=v+x \frac{d v}{d x}$, given differential equation reduces to

$v+x \frac{d v}{d x}=\frac{2 v-v^2}{2 v-1} \Rightarrow 3 v(1-v) d x=x(2 v-1) d v$