One phantom part of the curve

You have plotted xx.3(alpha.o1) and yy.3(alpha.o1) instead of xx.3(alpha.01) and yy.3(alpha.01)  i.e. You've used lower case o instead of the number 0.  If you correct this you get rid of the phantom part of the plot.

However, since alpha.o1 isn't defined anywhere in the worksheet as far as I can see, I'm puzzled as to why Mathcad plots anything at all here!!!

Alan