From 467a1d6d5446284fdb4abfdde7116bc09822ed96 Mon Sep 17 00:00:00 2001 From: "flyingscorpio@arch-desktop" Date: Sun, 19 Sep 2021 14:50:19 +0200 Subject: [PATCH] Add exercices Analyse --- analyse/exercices/Makefile | 16 ++++ analyse/exercices/main.tex | 178 +++++++++++++++++++++++++++++++++++++ 2 files changed, 194 insertions(+) create mode 100644 analyse/exercices/Makefile create mode 100644 analyse/exercices/main.tex diff --git a/analyse/exercices/Makefile b/analyse/exercices/Makefile new file mode 100644 index 0000000..4bce23d --- /dev/null +++ b/analyse/exercices/Makefile @@ -0,0 +1,16 @@ +filename=$(shell basename $(shell pwd)) +timestamp=$(shell date +%Y-%m-%d_%H:%M) + +all: snapshot + +snapshot: main.tex + @latexmk -pdf main.tex >/dev/null 2>&1 + @if ! cmp --silent build/main.pdf ${filename}_*.pdf; then \ + touch ${filename}_tmp.pdf; \ + rm ${filename}*.pdf; \ + cp build/main.pdf ${filename}_${timestamp}.pdf; \ + echo "Updated"; \ + fi + +clean: + @rm -rf build 2>/dev/null diff --git a/analyse/exercices/main.tex b/analyse/exercices/main.tex new file mode 100644 index 0000000..17fb9bd --- /dev/null +++ b/analyse/exercices/main.tex @@ -0,0 +1,178 @@ +\documentclass[a4paper,french,12pt]{article} + +\title{Analyse --- Exercices} +\author{} +\date{Dernière compilation~: \today{} à \currenttime} + +\usepackage{../../cours} +\usepackage{enumitem} +\usepackage{xfrac} + +\begin{document} + +\maketitle + +\section{Équations différentielles d'ordre 1} + + \paragraph{$(E_1)$} + + $y' - 2y = x^2$ + + \begin{enumerate}[label=\alph*)] + + \item Solution homogène + \begin{align*} + r = 2 \implies y_0 = \lambda e^{2x} + \end{align*} + + \item Solution particulière + \begin{align*} + \left\{ + \begin{array}{l} + y_1 = ax^2 + bx + c \\ + y_1' = 2ax + b \\ + \end{array} + \right. + \quad y_1' - 2 y_1 = x^2 \Leftrightarrow + 2ax + b - 2(ax^2 + bx + c) = x^2 \\ + \left\{ + \begin{array}{l} + -2a = 1 \\ + 2a - 2b = 0 \\ + b - 2c = 0 \\ + \end{array} + \right. + \Leftrightarrow + \left\{ + \begin{array}{l} + a = \sfrac{-1}{2} \\ + b = \sfrac{-1}{2} \\ + c = \sfrac{-1}{4} \\ + \end{array} + \right. \\ + \implies y_1 = -\frac{1}{2}x^2 -\frac{1}{2}x -\frac{1}{4} + \end{align*} + + \item Solution générale + + \begin{equation*} + y = y_0 + y_1 = \boxed{-\frac{1}{2}x^2 -\frac{1}{2}x -\frac{1}{4} + \lambda e^{2x}} + \end{equation*} + + \end{enumerate} + + \paragraph{$(E_2)$} + + $3y' - 9y = 7e^{3x}$ + + \begin{enumerate}[label=\alph*)] + + \item Solution homogène + \begin{align*} + r = 3 \implies y_0 = \lambda e^{3x} + \end{align*} + + \item Solution particulière + \begin{align*} + \left\{ + \begin{array}{l} + y_1 = ax e^{3x} \\ + y_1' = ae^{3x} + 3axe^{3x} = (3ax + a)e^{3x} \\ + \end{array} + \right. + \quad 3y_1' - 9y_1 = 7e^{3x} + &\Leftrightarrow 3(3ax + a)e^{3x} - 9axe^{3x} = 7e^{3x} \\ + &\Leftrightarrow (9ax + 3a)e^{3x} - 9axe^{3x} = 7e^{3x} \\ + &\Leftrightarrow 9ax + 3a - 9ax = 7 \\ + &\Leftrightarrow 3a = 7 \\ + &\Leftrightarrow a = \frac{7}{3} \\ + \implies y_1 = \frac{7}{3}xe^{3x} + \end{align*} + + \item Solution générale + + \begin{equation*} + y = y_0 + y_1 = \lambda e^{3x} + \frac{7}{3}xe^{3x} = \boxed{(\frac{7}{3}x + \lambda)e^{3x}} + \end{equation*} + + \end{enumerate} + + \paragraph{$(E_3)$} + + $2y' - 4y = 5e^{3x}$ + + \begin{enumerate}[label=\alph*)] + + \item Solution homogène + \begin{align*} + r = 2 \implies y_0 = \lambda e^{2x} + \end{align*} + + \item Solution particulière + \begin{align*} + \left\{ + \begin{array}{l} + y_1 = ae^{3x} \\ + y_1' = 3ae^{3x} \\ + \end{array} + \right. + \quad 2y_1' - 4y_1 = 5e^{3x} + &\Leftrightarrow 6ae^{3x} - 4ae^{3x} = 5e^{3x} \\ + &\Leftrightarrow 2a = 5 \\ + &\Leftrightarrow a = \frac{5}{2} \\ + \implies y_1 = \frac{5}{2}e^{3x} + \end{align*} + + \item Solution générale + + \begin{equation*} + y = y_0 + y_1 = \boxed{\lambda e^{2x} + \frac{5}{2}e^{3x}} + \end{equation*} + + \end{enumerate} + + \paragraph{$(E_4)$} + + $y' + 4y = 3\cos(2x)$ + + \begin{enumerate}[label=\alph*)] + + \item Solution homogène + \begin{align*} + r = -4 \implies y_0 = \lambda e^{-4x} + \end{align*} + + \item Solution particulière + \begin{align*} + \left\{ + \begin{array}{l} + y_1 = a\cos(2x) + b\sin(2x) \\ + y_1' = -2a\sin(2x) + 2b\cos(2x) \\ + \end{array} + \right. + \end{align*} + \begin{align*} + y_1' + 4y_1 = 3\cos(2x) + &\Leftrightarrow -2a\sin(2x) + 2b\cos(2x) + 4(a\cos(2x) + b\sin(2x)) = 3\cos(2x) \\ + &\Leftrightarrow + \left\{ + \begin{array}{l} + 4a + 2b = 3 \\ + 4b - 2a = 0 \\ + \end{array} + \right. + \Leftrightarrow + \left\{ + \begin{array}{l} + 4a + 2b = 3 \\ + 4a - 8b = 0 \\ + \end{array} + \right. + % TODO: finish + \end{align*} + + \end{enumerate} + +\section{Équations différentielles d'ordre 2} + +\end{document}