Get Help

Turn on suggestions

Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.

Showing results for

- Community
- :
- PTC Mathcad
- :
- PTC Mathcad
- :
- Re: problem with unit=0.0 when solve quadratic equ...

Options

- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Mute
- Printer Friendly Page

Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.

Showing results for

03-01-2019
05:41 AM

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Notify Moderator

03-01-2019
05:41 AM

problem with unit=0.0 when solve quadratic equation

Hello,

I am new to Mathcad,I have been using PTC Mathcad Prime 5 since yesterday.

I have a problem when I use solve and assume for this quadratic equation. All the variables have mm as unit. If I assume mm <> 0 then it works. The answer I am looking for is 233.41847464108950079 mm.

Ps. If I put = it shows the good answer (my bad, I was too frustrated about the if and else thing to try), but why does it show if and else?

Thank you

Solved! Go to Solution.

1 ACCEPTED SOLUTION

Accepted Solutions

03-01-2019
08:33 AM

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Notify Moderator

03-01-2019
08:33 AM

For numerical result (especially with units) you may consider using a numeric solve block instead of the symbolic solver:

2 REPLIES 2

03-01-2019
06:25 AM

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Notify Moderator

03-01-2019
06:25 AM

The symbolic processor in Mathcad (and Prime) does not know about units, it treats them as unknown variables.

You can write sol to be a function of Lp, Dp1 and Dp2, so instead of sol:=... you write sol(Lp,Dp1,Dp2):=...

Then you can evaluate sol(Lp,Dp1,Dp2)=

to get the answer.

Success!

Luc

03-01-2019
08:33 AM

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Notify Moderator

03-01-2019
08:33 AM