I have a lot of math to write so I tried to use align
inside gather
. When the column was over I was getting badboxes. So I used two gather
environments and the output is weird. What is happening and why? How can I fix that?
\documentclass[12pt]{article}
\usepackage[top=0.3in, bottom=1.2in, left=0.8in, right=0.8in]{geometry}
\usepackage{multicol}
\usepackage[utf8]{inputenc}
\setlength{\parindent}{0cm}
\usepackage{setspace}
\usepackage{xltxtra}
\usepackage{xgreek}
\setmainfont[Mapping=tex-text]{GFSDidot.otf}
\setsansfont[Mapping=tex-text]{GFSDidot.otf}
\usepackage[fleqn]{amsmath}
\usepackage{unicode-math}
\setlength{\mathindent}{0cm}
\newcommand{\3}{\vspace{0.3cm}}
\title{}
\author{}
\date{}
\begin{document}
\begin{multicols*}{2}
\begin{gather*}
\begin{aligned}
&\text{70}\\
&e^{jz}=\cos z+j\sin z\\
&\cos z=(1/2)(2\cos z)=\\
&=(1/2)(2\cos z+j\sin z-j\sin z)=\\
&=(1/2)(\cos z+j\sin z+\cos z-j\sin z)=\\
&=(1/2)(e^{jz}+e^{-jz})
\end{aligned}\\
\begin{aligned}
&\text{207}\\
&x(t)=A_{c}\cos \theta(t)\\
&\theta(t)=2\pi f_{c}t+\phi(t)\\
&\phi(t)=K_{p}m(t)\\
&x(t)=A_{c}\cos[2\pi f_{c}t+K_{p}m(t)]
\end{aligned}\\
\begin{aligned}
&\text{208}\\
&x(t)=A_{c}\cos \theta(t)\\
&\theta(t)=2\pi f_{c}t+\phi(t)\\
&\frac{d\phi(t)}{dt}=2\pi K_{f}m(t)\Rightarrow\\
&\Rightarrow \phi(t)=2\pi K_{f}\int\limits_{-\infty}^{t}m(\tau)d\tau\\
&x(t)=A_{c}\cos\left[2\pi f_{c}t+2\pi K_{f}\int\limits_{-\infty}^{t}m(\tau)d\tau\right]
\end{aligned}\\
\begin{aligned}
&\text{208}\\
&x(t)=A_{c}\cos\theta(t)=A_{c}\cos[2\pi f_{c}t+\phi(t)]\\
&\cos(a+b)=\cos a \cos b-\sin a \sin b\\
&\phi(t)=K_{p}m(t)\\
&\phi(t)=2\pi K_{f}\int\limits_{-\infty}^{t}m(\tau)d\tau
\end{aligned}\\
\begin{aligned}
&\text{265}\\
&g(t)=f(t)\ast h(t)=\int\limits_{-\infty}^{\infty}f(\tau)h(t-\tau)d\tau\\
&j(t)=\sum\limits_{k=-\infty}^{\infty}\delta(t-kT_{s})\Rightarrow\\
&\Rightarrow \mathcal{F}[j(t)]=\sum\limits_{k=-\infty}^{\infty}\mathcal{F}[\delta(t)]e^{j2\pi fkT_{s}}\\
&=\sum\limits_{k=-\infty}^{\infty}e^{j2\pi fkT_{s}}
\end{aligned}
\end{gather*}
\end{multicols*}
\end{document}
\documentclass[12pt]{article}
\usepackage[top=0.3in, bottom=1.2in, left=0.8in, right=0.8in]{geometry}
\usepackage{multicol}
\usepackage[utf8]{inputenc}
\setlength{\parindent}{0cm}
\usepackage{setspace}
\usepackage{xltxtra}
\usepackage{xgreek}
\setmainfont[Mapping=tex-text]{GFSDidot.otf}
\setsansfont[Mapping=tex-text]{GFSDidot.otf}
\usepackage[fleqn]{amsmath}
\usepackage{unicode-math}
\setlength{\mathindent}{0cm}
\newcommand{\3}{\vspace{0.3cm}}
\title{}
\author{}
\date{}
\begin{document}
\begin{multicols*}{2}
\begin{gather*}
\begin{aligned}
&\text{70}\\
&e^{jz}=\cos z+j\sin z\\
&\cos z=(1/2)(2\cos z)=\\
&=(1/2)(2\cos z+j\sin z-j\sin z)=\\
&=(1/2)(\cos z+j\sin z+\cos z-j\sin z)=\\
&=(1/2)(e^{jz}+e^{-jz})
\end{aligned}\\
\begin{aligned}
&\text{207}\\
&x(t)=A_{c}\cos \theta(t)\\
&\theta(t)=2\pi f_{c}t+\phi(t)\\
&\phi(t)=K_{p}m(t)\\
&x(t)=A_{c}\cos[2\pi f_{c}t+K_{p}m(t)]
\end{aligned}\\
\begin{aligned}
&\text{208}\\
&x(t)=A_{c}\cos \theta(t)\\
&\theta(t)=2\pi f_{c}t+\phi(t)\\
&\frac{d\phi(t)}{dt}=2\pi K_{f}m(t)\Rightarrow\\
&\Rightarrow \phi(t)=2\pi K_{f}\int\limits_{-\infty}^{t}m(\tau)d\tau\\
&x(t)=A_{c}\cos\left[2\pi f_{c}t+2\pi K_{f}\int\limits_{-\infty}^{t}m(\tau)d\tau\right]
\end{aligned}\\
\begin{aligned}
&\text{208}\\
&x(t)=A_{c}\cos\theta(t)=A_{c}\cos[2\pi f_{c}t+\phi(t)]\\
&\cos(a+b)=\cos a \cos b-\sin a \sin b\\
&\phi(t)=K_{p}m(t)\\
&\phi(t)=2\pi K_{f}\int\limits_{-\infty}^{t}m(\tau)d\tau
\end{aligned}\\
\end{gather*}
\begin{gather*}
\begin{aligned}
&\text{265}\\
&g(t)=f(t)\ast h(t)=\int\limits_{-\infty}^{\infty}f(\tau)h(t-\tau)d\tau\\
&j(t)=\sum\limits_{k=-\infty}^{\infty}\delta(t-kT_{s})\Rightarrow\\
&\Rightarrow \mathcal{F}[j(t)]=\sum\limits_{k=-\infty}^{\infty}\mathcal{F}[\delta(t)]e^{j2\pi fkT_{s}}\\
&=\sum\limits_{k=-\infty}^{\infty}e^{j2\pi fkT_{s}}
\end{aligned}
\end{gather*}
\end{multicols*}
\end{document}
Edit I:
This is the output with \raggedcolumns
as proposed in the comments and obviously there are problems concerning the space left in the first column and the height difference between the first and the second column. Also I don't understand why is there a problem in the first place with gather
environments.
\documentclass[12pt]{article}
\usepackage[top=0.3in, bottom=1.2in, left=0.8in, right=0.8in]{geometry}
\usepackage{multicol}
\usepackage[utf8]{inputenc}
\setlength{\parindent}{0cm}
\usepackage{setspace}
\usepackage{xltxtra}
\usepackage{xgreek}
\setmainfont[Mapping=tex-text]{GFSDidot.otf}
\setsansfont[Mapping=tex-text]{GFSDidot.otf}
\usepackage[fleqn]{amsmath}
\usepackage{unicode-math}
\setlength{\mathindent}{0cm}
\newcommand{\3}{\vspace{0.3cm}}
\title{}
\author{}
\date{}
\begin{document}
\raggedcolumns
\begin{multicols*}{2}
\begin{gather*}
\begin{aligned}
&\text{70}\\
&e^{jz}=\cos z+j\sin z\\
&\cos z=(1/2)(2\cos z)=\\
&=(1/2)(2\cos z+j\sin z-j\sin z)=\\
&=(1/2)(\cos z+j\sin z+\cos z-j\sin z)=\\
&=(1/2)(e^{jz}+e^{-jz})
\end{aligned}\\
\begin{aligned}
&\text{207}\\
&x(t)=A_{c}\cos \theta(t)\\
&\theta(t)=2\pi f_{c}t+\phi(t)\\
&\phi(t)=K_{p}m(t)\\
&x(t)=A_{c}\cos[2\pi f_{c}t+K_{p}m(t)]
\end{aligned}\\
\begin{aligned}
&\text{208}\\
&x(t)=A_{c}\cos \theta(t)\\
&\theta(t)=2\pi f_{c}t+\phi(t)\\
&\frac{d\phi(t)}{dt}=2\pi K_{f}m(t)\Rightarrow\\
&\Rightarrow \phi(t)=2\pi K_{f}\int\limits_{-\infty}^{t}m(\tau)d\tau\\
&x(t)=A_{c}\cos\left[2\pi f_{c}t+2\pi K_{f}\int\limits_{-\infty}^{t}m(\tau)d\tau\right]
\end{aligned}\\
\begin{aligned}
&\text{208}\\
&x(t)=A_{c}\cos\theta(t)=A_{c}\cos[2\pi f_{c}t+\phi(t)]\\
&\cos(a+b)=\cos a \cos b-\sin a \sin b\\
&\phi(t)=K_{p}m(t)\\
&\phi(t)=2\pi K_{f}\int\limits_{-\infty}^{t}m(\tau)d\tau
\end{aligned}\\
\end{gather*}
\begin{gather*}
\begin{aligned}
&\text{265}\\
&g(t)=f(t)\ast h(t)=\int\limits_{-\infty}^{\infty}f(\tau)h(t-\tau)d\tau\\
&j(t)=\sum\limits_{k=-\infty}^{\infty}\delta(t-kT_{s})\Rightarrow\\
&\Rightarrow \mathcal{F}[j(t)]=\sum\limits_{k=-\infty}^{\infty}\mathcal{F}[\delta(t)]e^{j2\pi fkT_{s}}\\
&=\sum\limits_{k=-\infty}^{\infty}e^{j2\pi fkT_{s}}
\end{aligned}
\end{gather*}
\end{multicols*}
\end{document}
inputenc
with XeLaTeX.\raggedcolumns
to fix this - you haven't provided many places for the columns to break...