Math equation solve issue

[Jason_power]

Hi experts,

I am trying to use Mathcad to solve the equation based on Equations 4 and equation 6.

below equations are from this paper.

https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9913417

when I try to use that to solve the equation. Mathcad can't find the answer in equation 6. but it is OK to get the answer by using eqaution4.

I know equations 4 and 6 are different, but I don't understand why I can find it. but this paper can.

so I would like to know if my operation is wrong.

ps: the version of Mathcad is Mathcad 15

[WalterSchrabmai]

Hi

In MathCAD Prime 3.1 it works fine

[WalterSchrabmai · Accepted solution]

it works also in MathCad v15

[Jason_power]

May I know where I was wrong?

I can't use the unit in my equation?

[LucMeekes]

You had defined Psi0 with a unit. There are two problems with that:

1. The argument of the exponential function must be unitless In order for that t must have the same unit as Psi0.

2. The symbolic processor of Mathcad doesn't know about units. At best it treats them as unknown variables.

You had defined Ig with a unit. The rhs of the second equation gets that same unit (because no unit elsewhere.), The lhs of the equation is a complex number without unit. That cannot be solved.

Success!
Luc

[Jason_power]

Got it, thanks.