cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
Showing results for 
Search instead for 
Did you mean: 

Simple? numeric + symbolic calculations

MC_BT_18
5-Regular Member

Simple? numeric + symbolic calculations

Hi! I'm new to mathcad and trying to calculate some very simple equations containing symbolics and numerical elements. I know which answer to get, but simply can't make mathcad return the wanted result.

 

1/2 * cos(v) * p * L + 1/2 * sin(v) * p* L

 

I look for the result looking like: 0.67 * p * L

 

I tried searching for solutions for this but can't really find an answer, but it seems so simple that I can't possibly think that what I look for isn't possible?

 

Any chance there's an easy workaround?

1 ACCEPTED SOLUTION

Accepted Solutions
LucMeekes
23-Emerald I
(To:MC_BT_18)

Mathcad has a numeric and a symbolic processor that work sort of independently from each other. The numeric processor is involved when you type = after an expression. It requires all variables to be numerically defined. It knows about units and conversion between them.
The symbolic processor is called with the right-arrow operator. It accepts undefined variables and always tries to produce an exact answer. Note that 1/2 is an exact ratio. In contrast 0.5 is a number with finite precision. The symbolic processor does not know units. It treats them as undefined variables.

Success!
Luc

View solution in original post

6 REPLIES 6
ttokoro
17-Peridot
(To:MC_BT_18)

Solved.

MC_BT_18
5-Regular Member
(To:ttokoro)

Thanks, although it's not quite there yet. I know this is a more exact solution, but was hoping for a numerical value before p * L. I guess this is as close as I can get?

ttokoro
17-Peridot
(To:MC_BT_18)

PDF attached.

LucMeekes
23-Emerald I
(To:MC_BT_18)

See what happens if you change at least one of the 1/2 to 0.5...

Success!
Luc
MC_BT_18
5-Regular Member
(To:LucMeekes)

Thankyou!!

 

I feel so stupid now, that I didn't try that myself. I knew it had to be a simple thing to do, I just couldn't get my head around it..

I'll remember this "trick" for next time!

LucMeekes
23-Emerald I
(To:MC_BT_18)

Mathcad has a numeric and a symbolic processor that work sort of independently from each other. The numeric processor is involved when you type = after an expression. It requires all variables to be numerically defined. It knows about units and conversion between them.
The symbolic processor is called with the right-arrow operator. It accepts undefined variables and always tries to produce an exact answer. Note that 1/2 is an exact ratio. In contrast 0.5 is a number with finite precision. The symbolic processor does not know units. It treats them as undefined variables.

Success!
Luc

View solution in original post

Announcements
Check out the latest
Mathcad Tip
"PTC Mathcad 15 / Prime 1-6 Update."