GATE 2020 PI – Question 12

Engineering Mathematics · Differential Equations · 1 mark · Multiple choice

An integrating factor for $dy/dx+my=e^{-mx}$ is

$e^m$
$e^{-m}$
$e^{-mx}$
$e^{mx}$

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Show answer and explanation

Correct answer: (D) $e^{mx}$

Explanation

A linear equation y′+P(x)y=Q(x) has integrating factor exp(∫P dx). Here P=m is constant, so the factor is e^(mx), D. Multiplication turns the left side into d(e^(mx)y)/dx.

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