diff --git a/appendices/appC_integral_tables.tex b/appendices/appC_integral_tables.tex index 4a582cb..46ead80 100644 --- a/appendices/appC_integral_tables.tex +++ b/appendices/appC_integral_tables.tex @@ -1,7 +1,7 @@ \section{Integral Tables} \label{app:integral_tables} -This appendix provides commonly used integral formulas encountered throughout the handbook. +This appendix provides commonly used integral formulas encountered throughout the handbook. See \cref{ch:first_order} for separable equations, \cref{ch:second_order_homogeneous} and \cref{ch:second_order_nonhomogeneous} for second-order ODE techniques, \cref{ch:laplace_transforms} for Laplace-domain integration, and \cref{ch:fourier_series} for trigonometric integrals in series expansions. \subsection{Basic Integrals} \label{sec:appC_basic} @@ -14,17 +14,17 @@ This appendix provides commonly used integral formulas encountered throughout th \toprule \textbf{Integrand} & \textbf{Result} \\ \midrule -$\displaystyle \int x^n \, dx$ & TBD \\ -$\displaystyle \int \frac{1}{x} \, dx$ & TBD \\ -$\displaystyle \int e^{ax} \, dx$ & TBD \\ -$\displaystyle \int a^x \, dx$ & TBD \\ -$\displaystyle \int \sin(ax) \, dx$ & TBD \\ -$\displaystyle \int \cos(ax) \, dx$ & TBD \\ -$\displaystyle \int \tan(ax) \, dx$ & TBD \\ -$\displaystyle \int \sec^2(ax) \, dx$ & TBD \\ -$\displaystyle \int \csc^2(ax) \, dx$ & TBD \\ -$\displaystyle \int \sec(ax)\tan(ax) \, dx$ & TBD \\ -$\displaystyle \int \csc(ax)\cot(ax) \, dx$ & TBD \\ +$\displaystyle \int x^n \, dx$ & $\displaystyle \frac{x^{n+1}}{n+1} + C \quad (n \neq -1)$ \\[8pt] +$\displaystyle \int \frac{1}{x} \, dx$ & $\displaystyle \ln|x| + C$ \\[8pt] +$\displaystyle \int e^{ax} \, dx$ & $\displaystyle \frac{e^{ax}}{a} + C$ \\[8pt] +$\displaystyle \int a^x \, dx$ & $\displaystyle \frac{a^x}{\ln(a)} + C$ \\[8pt] +$\displaystyle \int \sin(ax) \, dx$ & $\displaystyle -\frac{\cos(ax)}{a} + C$ \\[8pt] +$\displaystyle \int \cos(ax) \, dx$ & $\displaystyle \frac{\sin(ax)}{a} + C$ \\[8pt] +$\displaystyle \int \tan(ax) \, dx$ & $\displaystyle -\frac{\ln|\cos(ax)|}{a} + C = \frac{\ln|\sec(ax)|}{a} + C$ \\[8pt] +$\displaystyle \int \sec^2(ax) \, dx$ & $\displaystyle \frac{\tan(ax)}{a} + C$ \\[8pt] +$\displaystyle \int \csc^2(ax) \, dx$ & $\displaystyle -\frac{\cot(ax)}{a} + C$ \\[8pt] +$\displaystyle \int \sec(ax)\tan(ax) \, dx$ & $\displaystyle \frac{\sec(ax)}{a} + C$ \\[8pt] +$\displaystyle \int \csc(ax)\cot(ax) \, dx$ & $\displaystyle -\frac{\csc(ax)}{a} + C$ \\[8pt] \bottomrule \end{tabular} \end{table} @@ -40,12 +40,12 @@ $\displaystyle \int \csc(ax)\cot(ax) \, dx$ & TBD \\ \toprule \textbf{Integrand} & \textbf{Result} \\ \midrule -$\displaystyle \int e^{ax}\sin(bx)\,dx$ & TBD \\ -$\displaystyle \int e^{ax}\cos(bx)\,dx$ & TBD \\ -$\displaystyle \int x e^{ax}\,dx$ & TBD \\ -$\displaystyle \int x \sin(ax)\,dx$ & TBD \\ -$\displaystyle \int x \cos(ax)\,dx$ & TBD \\ -$\displaystyle \int \ln(x)\,dx$ & TBD \\ +$\displaystyle \int e^{ax}\sin(bx)\,dx$ & $\displaystyle \frac{e^{ax}\bigl(a\sin(bx) - b\cos(bx)\bigr)}{a^2 + b^2} + C$ \\[8pt] +$\displaystyle \int e^{ax}\cos(bx)\,dx$ & $\displaystyle \frac{e^{ax}\bigl(a\cos(bx) + b\sin(bx)\bigr)}{a^2 + b^2} + C$ \\[8pt] +$\displaystyle \int x e^{ax}\,dx$ & $\displaystyle e^{ax}\!\left(\frac{x}{a} - \frac{1}{a^2}\right) + C$ \\[8pt] +$\displaystyle \int x \sin(ax)\,dx$ & $\displaystyle \frac{\sin(ax)}{a^2} - \frac{x\cos(ax)}{a} + C$ \\[8pt] +$\displaystyle \int x \cos(ax)\,dx$ & $\displaystyle \frac{\cos(ax)}{a^2} + \frac{x\sin(ax)}{a} + C$ \\[8pt] +$\displaystyle \int \ln(x)\,dx$ & $\displaystyle x\ln(x) - x + C$ \\[8pt] \bottomrule \end{tabular} \end{table} @@ -61,11 +61,79 @@ $\displaystyle \int \ln(x)\,dx$ & TBD \\ \toprule \textbf{Integrand} & \textbf{Result} \\ \midrule -$\displaystyle \int \frac{1}{\sqrt{a^2 - x^2}}\,dx$ & TBD \\ -$\displaystyle \int \frac{1}{a^2 + x^2}\,dx$ & TBD \\ -$\displaystyle \int \frac{1}{x\sqrt{x^2 - a^2}}\,dx$ & TBD \\ -$\displaystyle \int \sqrt{a^2 - x^2}\,dx$ & TBD \\ -$\displaystyle \int \frac{1}{\sqrt{x^2 + a^2}}\,dx$ & TBD \\ +$\displaystyle \int \frac{1}{\sqrt{a^2 - x^2}}\,dx$ & $\displaystyle \arcsin\!\left(\frac{x}{a}\right) + C$ \\[8pt] +$\displaystyle \int \frac{1}{a^2 + x^2}\,dx$ & $\displaystyle \frac{1}{a}\arctan\!\left(\frac{x}{a}\right) + C$ \\[8pt] +$\displaystyle \int \frac{1}{x\sqrt{x^2 - a^2}}\,dx$ & $\displaystyle \frac{1}{a}\,\text{arcsec}\!\left(\frac{|x|}{a}\right) + C$ \\[8pt] +$\displaystyle \int \sqrt{a^2 - x^2}\,dx$ & $\displaystyle \frac{x}{2}\sqrt{a^2 - x^2} + \frac{a^2}{2}\arcsin\!\left(\frac{x}{a}\right) + C$ \\[8pt] +$\displaystyle \int \frac{1}{\sqrt{x^2 + a^2}}\,dx$ & $\displaystyle \ln\!\bigl|x + \sqrt{x^2 + a^2}\,\bigr| + C = \text{arcsinh}\!\left(\frac{x}{a}\right) + C$ \\[8pt] \bottomrule \end{tabular} \end{table} + +\subsection{Hyperbolic Integrals} +\label{sec:appC_hyperbolic} + +\begin{table}[htbp] +\centering +\caption{Hyperbolic Integral Formulas} +\label{tab:integrals_hyperbolic} +\begin{tabular}{l l} +\toprule +\textbf{Integrand} & \textbf{Result} \\ +\midrule +$\displaystyle \int \sinh(ax)\,dx$ & $\displaystyle \frac{\cosh(ax)}{a} + C$ \\[8pt] +$\displaystyle \int \cosh(ax)\,dx$ & $\displaystyle \frac{\sinh(ax)}{a} + C$ \\[8pt] +$\displaystyle \int \tanh(ax)\,dx$ & $\displaystyle \frac{\ln|\cosh(ax)|}{a} + C$ \\[8pt] +$\displaystyle \int \text{sech}^2(ax)\,dx$ & $\displaystyle \frac{\tanh(ax)}{a} + C$ \\[8pt] +$\displaystyle \int \text{csch}^2(ax)\,dx$ & $\displaystyle -\frac{\coth(ax)}{a} + C$ \\[8pt] +$\displaystyle \int \text{sech}(ax)\tanh(ax)\,dx$ & $\displaystyle -\frac{\text{sech}(ax)}{a} + C$ \\[8pt] +\bottomrule +\end{tabular} +\end{table} + +\subsection{Additional Common Integrals} +\label{sec:appC_additional} + +\begin{table}[htbp] +\centering +\caption{Additional Common Integral Formulas} +\label{tab:integrals_additional} +\begin{tabular}{l l} +\toprule +\textbf{Integrand} & \textbf{Result} \\ +\midrule +$\displaystyle \int \frac{1}{x^2 - a^2}\,dx$ & $\displaystyle \frac{1}{2a}\ln\left|\frac{x-a}{x+a}\right| + C$ \\[8pt] +$\displaystyle \int \frac{1}{a^2 - x^2}\,dx$ & $\displaystyle \frac{1}{2a}\ln\left|\frac{a+x}{a-x}\right| + C$ \\[8pt] +$\displaystyle \int \frac{x}{\sqrt{a^2 + x^2}}\,dx$ & $\displaystyle \sqrt{a^2 + x^2} + C$ \\[8pt] +$\displaystyle \int \frac{dx}{x\sqrt{a^2 + x^2}}$ & $\displaystyle -\frac{1}{a}\ln\left|\frac{a + \sqrt{a^2 + x^2}}{|x|}\right| + C$ \\[8pt] +$\displaystyle \int \sqrt{x^2 + a^2}\,dx$ & $\displaystyle \frac{x}{2}\sqrt{x^2 + a^2} + \frac{a^2}{2}\ln\!\bigl|x + \sqrt{x^2 + a^2}\,\bigr| + C$ \\[8pt] +$\displaystyle \int \sqrt{x^2 - a^2}\,dx$ & $\displaystyle \frac{x}{2}\sqrt{x^2 - a^2} - \frac{a^2}{2}\ln\!\bigl|x + \sqrt{x^2 - a^2}\,\bigr| + C$ \\[8pt] +\bottomrule +\end{tabular} +\end{table} + +\subsection{Integration by Parts Formula} +\label{sec:appC_parts} + +The method of integration by parts, frequently used in solving ODEs (\cref{ch:first_order}), is based on the product rule: +\begin{equation} +\label{eq:integration_by_parts} +\int u \, dv = uv - \int v \, du. +\end{equation} +Choose $u$ and $dv$ so that $\int v \, du$ is simpler than the original integral. + +\subsection{Reduction Formulas} +\label{sec:appC_reduction} + +Reduction formulas allow integrals of higher powers to be expressed in terms of lower powers: + +\begin{align} +\label{eq:reduction_sin} +\int \sin^n(x) \, dx &= -\frac{1}{n}\sin^{n-1}(x)\cos(x) + \frac{n-1}{n}\int \sin^{n-2}(x) \, dx, \\ +\label{eq:reduction_cos} +\int \cos^n(x) \, dx &= \frac{1}{n}\cos^{n-1}(x)\sin(x) + \frac{n-1}{n}\int \cos^{n-2}(x) \, dx, \\ +\label{eq:reduction_xe} +\int x^n e^{ax} \, dx &= \frac{x^n e^{ax}}{a} - \frac{n}{a}\int x^{n-1}e^{ax} \, dx. +\end{align} + +These formulas are especially useful when solving higher-order ODEs (\cref{ch:second_order_homogeneous,ch:second_order_nonhomogeneous}) and evaluating Fourier coefficients (\cref{ch:fourier_series}).