Math & Science ⇒ alignment of "="

[abu aasiyah]

Hello all,

Can someone assist me in aligning the "=" in the following expressions. In each expression there are two "=" signs. The second row is not aligned. Any suggestions?

The code is:

Code: Select all

\documentclass[12pt,a4paper]{article} 
\usepackage[latin1]{inputenc} 
\usepackage[danish]{babel} % danske overskrifter
\usepackage[T1]{fontenc} 
\usepackage{lmodern} 
\usepackage{graphicx} 
\usepackage{mathtools}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{ulem}
\usepackage{textcomp}
\usepackage{tikz}
\usepackage{color}
\usepackage{arcs}
\usepackage{amsthm}
\usepackage[hang,small,bf]{caption}

\setlength{\abovecaptionskip}{5pt}
\setlength{\captionmargin}{65pt}

\○begin{document}

\noindent Vindlasten, $\theta=0$, på zonerne $A$, $B$, $C$, $D$ og $E$ fås da til:
\begin{alignat*}{2}
w_{e,A_{0}}&=0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot (-1,2) \cdot \tfrac{20\text{m}}{5}&=-2,88\tfrac{\text{kN}}{\text{m}} \\
w_{e,B_{0}}&=0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot (-0,8) \cdot \tfrac{4\cdot 20\text{m}}{5}&=-7,68\tfrac{\text{kN}}{\text{m}} \\
w_{e,C_{0}}&=0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot (-0,5) \cdot (28,8 \text{m}-20\text{m})&=-2,64\tfrac{\text{kN}}{\text{m}} \\
w_{e,D_{0}}&=0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot 0,71 \cdot 72\text{m}&=30,67\tfrac{\text{kN}}{\text{m}} \\
w_{e,E_{0}}&=0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot (-0,33) \cdot 72\text{m}&=-14,26\tfrac{\text{kN}}{\text{m}} \\
\end{alignat*}

\noindent Formfaktorerne for tilfældet, hvor vinden har en vinkel $\theta=90^{\circ}$ er de samme som for til tilfældet, hvor $\theta=0$. For situationen, hvor vindlasten virker med vinklen $\theta=90^{\circ}$ bliver vindlasten på zonerne $A$, $B$, $C$, $D$ og $E$:
\begin{alignat*}{2}
w_{e,A_{90}}&=0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot (-1,2) \cdot \tfrac{20\text{m}}{5}&=-2,88\tfrac{\text{kN}}{\text{m}} \\
w_{e,B_{90}}&=0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot (-0,8) \cdot \tfrac{4\cdot 20\text{m}}{5}&=-7,68\tfrac{\text{kN}}{\text{m}} \\
w_{e,C_{90}}&=0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot (-0,5) \cdot (72 \text{m}-20\text{m})&=-15,6\tfrac{\text{kN}}{\text{m}} \\
w_{e,D_{90}}&=0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot 0,71 \cdot 28,8\text{m}&=12,27\tfrac{\text{kN}}{\text{m}} \\
w_{e,E_{90}}&=0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot (-0,33) \cdot 28,8\text{m}&=-5,70\tfrac{\text{kN}}{\text{m}} \\
\end{alignat*}

\end{document}

[localghost]

The alignat environment is a little bit tricky. Consider it as an array with the following alignments.

Code: Select all

r&=l  &   r&=l

Since you don't have the second right aligned column (r), you have to insert two ampersands (»&«). Your example then looks like the following.

Code: Select all

\documentclass[12pt,a4paper]{article}
\usepackage{T1]{fontenc}
\usepackage[latin1]{inputenc}
\usepackage[danish]{babel} % danske overskrifter
\usepackage{amsmath}
\usepackage{lmodern}

\begin{document}
  \noindent Vindlasten, $\theta=0$, på zonerne $A$, $B$, $C$, $D$ og $E$ fås da til:
  \begin{alignat*}{2}
    w_{e,A_{0}} &= 0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot (-1,2) \cdot \tfrac{20\text{m}}{5} &&= -2,88\tfrac{\text{kN}}{\text{m}} \\
    w_{e,B_{0}} &= 0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot (-0,8) \cdot \tfrac{4\cdot 20\text{m}}{5} &&= -7,68\tfrac{\text{kN}}{\text{m}} \\
    w_{e,C_{0}} &= 0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot (-0,5) \cdot (28,8 \text{m}-20\text{m}) &&= -2,64\tfrac{\text{kN}}{\text{m}} \\
    w_{e,D_{0}} &= 0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot 0,71 \cdot 72\text{m} &&= 30,67\tfrac{\text{kN}}{\text{m}} \\
    w_{e,E_{0}} &= 0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot (-0,33) \cdot 72\text{m} &&= -14,26\tfrac{\text{kN}}{\text{m}} \\
  \end{alignat*}

  \noindent Formfaktorerne for tilfældet, hvor vinden har en vinkel $\theta=90^{\circ}$ er de samme som for til tilfældet, hvor $\theta=0$. For situationen, hvor vindlasten virker med vinklen $\theta=90^{\circ}$ bliver vindlasten på zonerne $A$, $B$, $C$, $D$ og $E$:
  \begin{alignat*}{2}
    w_{e,A_{90}} &= 0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot (-1,2) \cdot \tfrac{20\text{m}}{5} &&= -2,88\tfrac{\text{kN}}{\text{m}} \\
    w_{e,B_{90}} &= 0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot (-0,8) \cdot \tfrac{4\cdot 20\text{m}}{5} &&= -7,68\tfrac{\text{kN}}{\text{m}} \\
    w_{e,C_{90}} &= 0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot (-0,5) \cdot (72 \text{m}-20\text{m}) &&= -15,6\tfrac{\text{kN}}{\text{m}} \\
    w_{e,D_{90}} &= 0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot 0,71 \cdot 28,8\text{m} &&= 12,27\tfrac{\text{kN}}{\text{m}} \\
w_{e,E_{90}} &= 0,6\tfrac{\text{kN}}{\text{m}^{2}} \cdot (-0,33) \cdot 28,8\text{m} &&= -5,70\tfrac{\text{kN}}{\text{m}} \\
  \end{alignat*}
\end{document}

You can find more information about that in the amsmath manual and in the »Math mode« document.

Consider to use the siunitx package for typesetting expressions which contain units.


Best regards
Thorsten