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Ch. 9 - Differential Equations
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243Non è quello che usi tu?Cambia libro di testo
Capitolo 9, Problema 9.R.32a

A first-order equation Consider the equation t² y′(t) + 2ty(t) = e⁻ᵗ
a. Show that the left side of the equation can be written as the derivative of a single term.

Guida verificata passo dopo passo
1
Start with the given differential equation: \(t^{2} y'(t) + 2t y(t) = e^{-t}\).
Notice that the left side resembles the product rule for derivatives. Recall the product rule: \(\frac{d}{dt}[u(t)v(t)] = u'(t)v(t) + u(t)v'(t)\).
Identify \(u(t)\) and \(v(t)\) such that \(\frac{d}{dt}[u(t) y(t)] = t^{2} y'(t) + 2t y(t)\). Here, let \(u(t) = t^{2}\) and \(v(t) = y(t)\).
Compute \(u'(t) = \frac{d}{dt} t^{2} = 2t\). Then, by the product rule, \(\frac{d}{dt}[t^{2} y(t)] = 2t y(t) + t^{2} y'(t)\), which matches the left side of the equation.
Therefore, the left side can be written as \(\frac{d}{dt}[t^{2} y(t)]\).

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