I want to find torque from standard power formula without changing equation to t=p*30/(pi.n)

If you need the calculation more often with different arguments, you might consider creating a function for torque

In case the formula is more complicated and cannot be solved symbolically anymore, you will have to resort to a numerical solve block:

and of course you could turn this solve block in a function, too, if you like. You would simply write torque(P, omega):=Find(tau).

As you could see - when you define a variable with unit rpm, you already define omega = n* 2pi, not just n. And there is no need to manually convert minutes to seconds as Mathcad takes care of the correct units anyway.

After all, the suggested methods all seem overkill, as it would be to easy to simply do

but I guess you have more complicated formulas in mind which cannot solve for a variable that easy.

Werner

BTW, using the symbolical keyword "float" is dangerous and usually not recommended as it affects not only the display of the result but also the precision of the whole calculation. So you might lose significant precision!

It is not working in Express Prime 3.1

Straight up!

Now can tell how to find the unknown variable Drr..it get complicated to go simplify...

or