Mathcad not able to plot a graph?

In order to plot, Prime needs the function to be numerically known. That means that all symbols you use must be numerically defined, have a value.

In your function you have two DIFFERENT symbols V, one is blue, it is a unit (for Volt), and while that is numerically defined as 1 V, you have defined the function such that you transform it symbolically. The symbolic processor, which is happy to deal with (numerically undefined) symbols, doesn't know about units and treats them as (unknown) symbols. So it transforms the V into a V. Now you want to plot it. That's a task for the numeric processor, that doesn't know the value of V, and (rightfully) complains that the function is 'undefined'.

Possible solutions:

1. Don't transform the function symbolically.

2. Define V:=1 V. before the function definition.

Success!
Luc

So now you ask: But what about   t  , I didn't define   t   numerically?

Prime allows ONE variable to be undefined for a plot, that is the argument to the function, which it automatically and invisibly (behind the scenes) defines as a range variable from -10 to 10. That's why the plot shows that range along the x-axis.

But it's OK to override that automatic definition If you define t:=0,0.1...1 before the plot, it'll plot your function from t=0 to 1 in steps of 0.1.