Target Exam

CUET

Subject

Section B1

Chapter

Differential Equations

Question:

Find the general solution of the differential equation: $xdy = (e^y - 1)dx$.

Options:

$y = \ln|x(e^y - 1)| + C$

$1 - e^{-y} = Cx$

$e^y = x + C$

$y = e^x - \ln|x| + C$

Correct Answer:

$1 - e^{-y} = Cx$

Explanation:

The correct answer is Option (2) → $1 - e^{-y} = Cx$ ##

Given differential equation can be written as

$\frac{dy}{dx} = \frac{1}{x}(e^y - 1)$

$\Rightarrow \int \frac{dy}{e^y - 1} = \int \frac{dx}{x}$

$\Rightarrow \int \frac{e^{-y}}{1 - e^{-y}} dy = \int \frac{dx}{x}$

$\Rightarrow \log |1 - e^{-y}| = \log |x| + \log C$

$\Rightarrow 1 - e^{-y} = Cx$