my first question is: what is the difference between them |
Vast. It's best described by a brief history.
Mathcad started (surprise!) at version 1, and advanced steadily up to version 11. When it went to version 12 a number of things were changed, and the version was generally considered to be worse than 11. From 12 to 15 it gradually improved again, and it is debatable whether version 11 or version 15 is the best version to date. Each has their advantages. Version 14 was the last Mathsoft version, and after PTC purchased Mathcad they released version 15, which is not much more than another service release of 14. That was the last PTC version in that sequence, because they then decided to rewrite Mathcad almost from the ground up, and launched Mathcad Prime. Prime 1.0 was so functionally limited it was laughable. Version 2.0 was better, and version 3.0 was better still, but Prime 3.0 is still very limited compared to Mathcad 15 (that is not to say that it has no advantages, but for most long term users the disadvantages far outweigh the advantages).
So:
Mathcad 15: By far the most powerful, by far the largest number of existing worksheets, but no long term future. Mathcad 15 worksheets can be converted to Prime 3.0 worksheets, but they usually require some editing to make them work. Unless they use Mathcad 15 features that Prime does not support of course, in which case it may be impossible to get them to work.
Prime 3.0: Very limited compared to Mathcad 15, but Prime will improve with new versions (at the current rate, it will be many years before it catches up to Mathcad 15 though). Prime worksheets cannot be converted to Mathcad 15 worksheets, so if you run into some limitation of Prime your only options may be to give up, use a pencil and paper, or retype everything into Mathcad 15.
