General ⇒ Equations are sequentially tabbing throughout document

[yogester]

First time poster.

I have been using LaTeX to typeset my documents for a while but I have not needed to have several equations in a row before so I have not encountered this issue before. Please excuse any naughty cheats that I have taken.... (but feel free to suggest any hints too! I know my doing [10pt} after each line and [40pt] after each equation is not correct but it gets the job done and I have not worked out a more elegant approach)

Back to the main problem, each time I put an equation together that is in the next {align*} environment it seems to line itself up with the tab break in the environment above it.

Here is the output:-



Here is my code:-

Code: Select all

\section*{Question 2}
\renewcommand{\labelenumi}{\Alph{enumi}.}
\renewcommand{\labelenumii}{\alph{enumii}.}

\begin{enumerate}
\item


\begin{align*}
	U &= \dfrac{1}{ \sum \dfrac{x}{k} + \sum \dfrac{1}{h}}  \nonumber  \\[10pt]
	&= \dfrac{1}{\dfrac{1}{h_i} +  \dfrac{x}{k} + \dfrac{1}{h_o}}  \nonumber \\[10pt]
	&= \dfrac{1}{\dfrac{1}{260} + \dfrac{3.25 \times 10^{-3}}{17} + \dfrac{1}{8}}  \nonumber\\[10pt]
	&= \dfrac {1}{3.84 \times 10^{-3} +  1.91 \times 10^{-4}  + 0.125}  \nonumber\\[10pt]
	&= \dfrac{1}{0.129} \nonumber\\[10pt]
	&= 7.75 \; W/m^2 \cdot ^\circ K \nonumber
\end{equation*}

\item

\begin{align*}
	A &= \pi D h + \dfrac{\pi D^2}{4}  \nonumber  \\[10pt]
	&= 2.9 \cdot 3.5 \cdot \pi + \dfrac{2.9^2 \cdot \pi}{4}  \nonumber  \\[10pt]
	&= 38.5 \; m^2 \nonumber \\[40pt]
	q &= U \cdot A \cdot \Delta T  \nonumber \\[10pt]
	&= 7.75 \times \38.5 \times 14 \nonumber \\[10pt]
	&= 4.2 \; kW \nonumber	
\end{align*}

\item

\begin{align*}
	V &= \dfrac{\pi D^2}{4} \cdot h \nonumber \\[10pt]
	&= 23.12 \; m^3 \nonumber 
\end{align*}	

\end{enumerate}

Thanks very much for any input!!!!

[Stefan Kottwitz]

Hi yogester,

welcome to the board!
Those math environments are centered. If you don't want it, set the document class option fleqn.
Further you are closing the first align* environment by \end{equation*}, replace it by \end{align*}.

Instead of adding [10pt] each line try

Code: Select all

\addtolength{\jot}{10pt}

once.

Stefan

[yogester]

thanks stefan!

it was poor copy pasting of my code that led to the \end{equation*} slipping in there...

I will try to use the \addtolength{\jot}{10pt} - do I just place it in the preamble?

yogester

[Juanjo]

Try this:

Code: Select all

\begin{enumerate}
\addtolength{\jot}{10pt}
\item
$\begin{aligned}[t]
   U &= \dfrac{1}{ \sum \dfrac{x}{k} + \sum \dfrac{1}{h}}  \\
   &= \dfrac{1}{\dfrac{1}{h_i} +  \dfrac{x}{k} + \dfrac{1}{h_o}} \\
   &= \dfrac{1}{\dfrac{1}{260} + \dfrac{3.25 \times 10^{-3}}{17} + \dfrac{1}{8}} \\
   &= \dfrac {1}{3.84 \times 10^{-3} +  1.91 \times 10^{-4}  + 0.125} \\
   &= \dfrac{1}{0.129}\\
   &= 7.75 \; W/m^2 \cdot ^\circ K
\end{aligned}$

\item
$\begin{aligned}[t]
   A &= \pi D h + \dfrac{\pi D^2}{4}  \\
   &= 2.9 \cdot 3.5 \cdot \pi + \dfrac{2.9^2 \cdot \pi}{4}  \\
   &= 38.5 \; m^2 \\
   q &= U \cdot A \cdot \Delta T  \\
   &= 7.75 \times \ 38.5 \times 14 \\
   &= 4.2 \; kW   
\end{aligned}$

\item
$\begin{aligned}[t]
   V &= \dfrac{\pi D^2}{4} \cdot h \\
   &= 23.12 \; m^3 
\end{aligned}$   

\end{enumerate}

The SIunits package will help you to correctly type units. Consider also if you really need to vertically align expressions instead of wrtting them in the same line (there is enough space in most rows!).

[yogester]

Didn't know there was an SIunits package - thanks for that!

What is the difference between {aligned} and {align*} other than not needing to suppress equation numbering?

Thanks!

[Juanjo]

What is the difference between {aligned} and {align*} other than not needing to suppress equation numbering?

aligned should always be used inside other math environment, like equation, multline, align, $...$,... Just a simple example:

Code: Select all

\begin{equation*}
   \nabla f(x,y)=\mathbf{0}
   \Longleftrightarrow\left\{
   \begin{aligned}
      f_x(x,y)&=0 \\
      f_y(x,y)&=0
   \end{aligned}
   \right.
\end{equation*}

You should read the documentation of the amsmath package. There are several environments, like aligned, which prove to be quite useful.