### Author Topic: LaTex broken in 2nd and subsequent previews  (Read 2193 times)

#### grmcdorman

• Venus
• Posts: 85
##### LaTex broken in 2nd and subsequent previews
« 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.

#### LunarOrbit

• Jupiter
• Posts: 690
##### Re: LaTex broken in 2nd and subsequent previews
« Reply #1 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

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

So, solving for vf:

 \frac{1}{2}m_f v_f^2 = \frac{1}{2}m_i v_i^2 - e v_f^2 = \frac{2 ( 1/2 m_i v_i^2 - e ) }{m_f} v_f = \sqrt{ \frac{m_i v_i^2 - 2e}{m_f} } 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?
It suddenly struck me that that tiny pea, pretty and blue, was the Earth.
I put up my thumb and shut one eye, and my thumb blotted out the planet Earth.
I didn't feel like a giant. I felt very, very small.
- Neil Armstrong (1930-2012)

#### LunarOrbit

• Jupiter
• Posts: 690
##### Re: LaTex broken in 2nd and subsequent previews
« Reply #2 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

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

So, solving for vf:

 \frac{1}{2}m_f v_f^2 = \frac{1}{2}m_i v_i^2 - e v_f^2 = \frac{2 ( 1/2 m_i v_i^2 - e ) }{m_f} v_f = \sqrt{ \frac{m_i v_i^2 - 2e}{m_f} } 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?

It suddenly struck me that that tiny pea, pretty and blue, was the Earth.
I put up my thumb and shut one eye, and my thumb blotted out the planet Earth.
I didn't feel like a giant. I felt very, very small.
- Neil Armstrong (1930-2012)

#### LunarOrbit

• Jupiter
• Posts: 690
##### Re: LaTex broken in 2nd and subsequent previews
« Reply #3 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.
It suddenly struck me that that tiny pea, pretty and blue, was the Earth.
I put up my thumb and shut one eye, and my thumb blotted out the planet Earth.
I didn't feel like a giant. I felt very, very small.
- Neil Armstrong (1930-2012)

#### grmcdorman

• Venus
• Posts: 85
##### Re: LaTex broken in 2nd and subsequent previews
« Reply #4 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>).