4

I'm trying to set up my equations for 3 hours and it's driving me crazy. I'm new in LaTeX so I don't master it at all.

This is the closest, with the simplest code, that I could get.

\documentclass[a4paper,11pt]{report}

\usepackage{amsmath}
\begin{document}

\begin{align}
dX(t)=&-f1*X(t)L(t)dt+g1*U(t)dt\\
    &-\sqrt{f1*X(t)L(t)}dW1(t)+\sqrt{g1*U(t)}dW2(t)
\end{align}
\begin{align}
dL(t)=&-f1*X(t)L(t)dt+g1*U(t)dt-f2*U(t)L(t)dt+g2*Y(t)dt\\
    &-\sqrt{f1*X(t)L(t)}dW1(t)+\sqrt{g1*U(t)}dW2(t)\\
    &-\sqrt{f2*U(t)L(t)}dW3(t)+\sqrt{g2*Y(t)}dW4(t)
\end{align}
\begin{align}
dU(t)=&f1*X(t)L(t)dt-g1*U(t)dt-f2*U(t)L(t)dt+g2*Y(t)dt\\
    &+\sqrt{f1*X(t)L(t)}dW1(t)-\sqrt{g1*U(t)}dW2(t)\\
    &-\sqrt{f2*U(t)L(t)}dW3(t)+\sqrt{g2*Y(t)}dW4(t)
\end{align}
\begin{align}
dY(t)=&f2*U(t)L(t)dt-g2*Y(t)dt\\
    &+\sqrt{f2*U(t)L(t)}dW3(t)-\sqrt{g2*Y(t)}dW4(t)
\end{align}
\end{document}

And it's giving me this this

It's close to what I want but I want the dX, dL, ... to be aligned aswell. And, if possible, but not very important, to get only one number of ref. for the whole set.

I tried numerous ways with align, split, aligned and I couldn't do it.

I've the conviction that the answer is very simple but I don't know what to try anymore, I've read so many post about it here and I'm still blocked.

Thank you.

Edit :

As suspected, it wasn't tricky at all, thank you very much.

3

Key changes:

  1. a single align block, with extra \\ for blank lines

  2. ={}&, not =&, to get the proper spacing around =

  3. \notag for unnumbered lines

Here is the revision.

\documentclass[a4paper,11pt]{report}
\usepackage[margin=1in]{geometry}
\usepackage{amsmath}
\begin{document}
\begin{align}
dX(t)={}&-f1*X(t)L(t)dt+g1*U(t)dt\notag\\
    &-\sqrt{f1*X(t)L(t)}dW1(t)+\sqrt{g1*U(t)}dW2(t)\\
\notag\\
dL(t)={}&-f1*X(t)L(t)dt+g1*U(t)dt-f2*U(t)L(t)dt+g2*Y(t)dt\notag\\
    &-\sqrt{f1*X(t)L(t)}dW1(t)+\sqrt{g1*U(t)}dW2(t)\notag\\
    &-\sqrt{f2*U(t)L(t)}dW3(t)+\sqrt{g2*Y(t)}dW4(t)\\
\notag\\
dU(t)={}&f1*X(t)L(t)dt-g1*U(t)dt-f2*U(t)L(t)dt+g2*Y(t)dt\notag\\
    &+\sqrt{f1*X(t)L(t)}dW1(t)-\sqrt{g1*U(t)}dW2(t)\notag\\
    &-\sqrt{f2*U(t)L(t)}dW3(t)+\sqrt{g2*Y(t)}dW4(t)\\
\notag\\
dY(t)={}&f2*U(t)L(t)dt-g2*Y(t)dt\notag\\
    &+\sqrt{f2*U(t)L(t)}dW3(t)-\sqrt{g2*Y(t)}dW4(t)
\end{align}
\end{document}

enter image description here

3

Nest split in align:

\documentclass[a4paper,11pt]{report}
\usepackage{amsmath}

\newcommand{\diff}{\mathop{}\!d}

\begin{document}

\begin{align}
\begin{split}
\diff X(t)&=-f_1*X(t)L(t)\diff t+g_1*U(t)\diff t\\
     &\qquad-\sqrt{f_1*X(t)L(t)}\diff W_1(t)+\sqrt{g_1*U(t)}\diff W_2(t)
\end{split}\\[1ex]
\begin{split}
\diff L(t)&=-f_1*X(t)L(t)\diff t+g_1*U(t)\diff t\\
     &\qquad-f_2*U(t)L(t)\diff t+g_2*Y(t)\diff t\\
     &\qquad-\sqrt{f_1*X(t)L(t)}\diff W_1(t)+\sqrt{g_1*U(t)}\diff W_2(t)\\
     &\qquad-\sqrt{f_2*U(t)L(t)}\diff W_3(t)+\sqrt{g_2*Y(t)}\diff W_4(t)
\end{split}\\[1ex]
\begin{split}
\diff U(t)&=f_1*X(t)L(t)\diff t-g_1*U(t)\diff t\\
     &\qquad-f_2*U(t)L(t)\diff t+g_2*Y(t)\diff t\\
     &\qquad+\sqrt{f_1*X(t)L(t)}\diff W_1(t)-\sqrt{g_1*U(t)}\diff W_2(t)\\
     &\qquad-\sqrt{f_2*U(t)L(t)}\diff W_3(t)+\sqrt{g_2*Y(t)}\diff W_4(t)
\end{split}\\[1ex]
\begin{split}
\diff Y(t)&=f_2*U(t)L(t)\diff t-g_2*Y(t)\diff t\\
     &\qquad+\sqrt{f_2*U(t)L(t)}\diff W_3(t)-\sqrt{g_2*Y(t)}\diff W_4(t)
\end{split}
\end{align}
\end{document}

I added some vertical space between the blocks in order to better separate them.

I also added the \diff macro for improving the appearance of the differentials and also used subscripts. Are you sure about *?

enter image description here

  • 2
    Battle of the Leprechauns! – Steven B. Segletes Dec 29 '16 at 0:49
  • Yes, I need to add subscripts and remove * but it wasn't my main issue at all, one problem at a time. :p – Emil Cioran Dec 29 '16 at 0:55
  • Your proposition is very good and look slightly better than the other Leprechaun one but I have too much equations to rework to handle it, for the importance of my report at least. Anyway, the differential d is a nice addition! Thank you. – Emil Cioran Dec 29 '16 at 0:58

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.