# ApolloHoax.net

## Off Topic => Tech Support => Topic started by: grmcdorman on January 05, 2013, 10:03:18 AM

Title: LaTex broken in 2nd and subsequent previews
Post by: grmcdorman on January 05, 2013, 10:03:18 AM
Easiest way to reproduce:
• Go to the LaTex thread in this forum.
• Hit 'Quote' on the last post.
• Hit 'Preview'
• Hit 'Preview' on the preview page

Expected result: Preview still shows LaTex.
Observed result: Preview shows raw jstex.
Title: Re: LaTex broken in 2nd and subsequent previews
Post by: LunarOrbit on January 05, 2013, 10:43:25 AM
Copied for testing...

OK, looking up the LaTex, I can do Heiwa's equations in a more readable form. This gives another way of looking at the problem.

So, given:
 mi Initial mass vi Initial velocity mf Final mass vf Final velocity e Energy (J) available from fuel combustion

 [jstex]\frac{1}{2}m_i v_i^2 - \frac{1}{2}m_f v_f^2 = e[/jstex] Equ. 1

So, solving for vf:

 [jstex]\frac{1}{2}m_f v_f^2 = \frac{1}{2}m_i v_i^2 - e[/jstex] [jstex]v_f^2 = \frac{2 ( 1/2 m_i v_i^2 - e ) }{m_f}[/jstex] [jstex]v_f = \sqrt{ \frac{m_i v_i^2 - 2e}{m_f} }[/jstex] Equ.2

Heiwa, do you:
• Agree that this is correct?
• Agree that using Equ. 2, we can calculate the spacecraft's final velocity, given the initial velocity and mass, the final mass, and the energy from the burned fuel?
Title: Re: LaTex broken in 2nd and subsequent previews
Post by: LunarOrbit on January 05, 2013, 10:43:58 AM
Copied for testing...

OK, looking up the LaTex, I can do Heiwa's equations in a more readable form. This gives another way of looking at the problem.

So, given:
 mi Initial mass vi Initial velocity mf Final mass vf Final velocity e Energy (J) available from fuel combustion

 [jstex]\frac{1}{2}m_i v_i^2 - \frac{1}{2}m_f v_f^2 = e[/jstex] Equ. 1

So, solving for vf:

 [jstex]\frac{1}{2}m_f v_f^2 = \frac{1}{2}m_i v_i^2 - e[/jstex] [jstex]v_f^2 = \frac{2 ( 1/2 m_i v_i^2 - e ) }{m_f}[/jstex] [jstex]v_f = \sqrt{ \frac{m_i v_i^2 - 2e}{m_f} }[/jstex] Equ.2

Heiwa, do you:
• Agree that this is correct?
• Agree that using Equ. 2, we can calculate the spacecraft's final velocity, given the initial velocity and mass, the final mass, and the energy from the burned fuel?

Title: Re: LaTex broken in 2nd and subsequent previews
Post by: LunarOrbit on January 05, 2013, 10:46:05 AM
Observed result: Preview shows raw jstex.

I see what you mean. Fortunately it still posts as LaTex if you submit it. I'm not sure if I can fix it myself, I'll have to wait for an update from the plugin developer.
Title: Re: LaTex broken in 2nd and subsequent previews
Post by: grmcdorman on January 05, 2013, 02:36:51 PM
FYI, it isn't exclusive to the quote function; it's the preview on the preview page (i.e. press Preview below Quick Reply, then Preview on the subsequent page). The steps I gave were what seemed to be the simplest to reproduce the issue - which is always important with bugs (and other things <grin>).