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Simple? numeric + symbolic calculations

SOLVED
Level 7

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

Re: Simple? numeric + symbolic calculations

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
6 REPLIES 6

Re: Simple? numeric + symbolic calculations

Solved.

Re: Simple? numeric + symbolic calculations

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?

Re: Simple? numeric + symbolic calculations

PDF attached.

Re: Simple? numeric + symbolic calculations

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

Success!
Luc

Re: Simple? numeric + symbolic calculations

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

Re: Simple? numeric + symbolic calculations

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!