I'm at wits end trying to figure this simple bug out that only my computer ever seems to run into. Why am I getting an error when I try to compute the last two variables at the end of my sheet. I've tried Googling it, and my friend has typed the exact way I have, and does not get this error. This one thing is prohibitting me from completing a project that is far too simple.
Mathcad has two completely different subscripts You have used the literal index (Lx.i) which is simply part of the variable name, just lowered and smaller. But as you want to create a vector you should have used the vector/matrix index (Lx[i).
They both look very similar but you can notice the difference if you click in the region - then you see the dot in your expressions which shouldn't be there.
If you don't like keyboard shorts - you get the literal subscript from the formatting menu bar as for normal text and the matrix subscript from the Vector and Matrix Toolbar.