one of the most confusing thing for me with learning Maple, is pi vs. Pi. I keep mixing them up since do not remember half the time which one to use.

What is the point of having both? Mathematica only has Pi. If one wants numerical value for it, simply do N[Pi] which is similar to Maple evalf(Pi).

I just spend 5 minutes trying to figure why int((sin(x))^3*sin(k*x),x=-pi..pi); was giving me

While in Mathematica it gives

Then I noticed the Pi vs. pi, and now Maple gives same output.

Why pi was even introduced? was this done early on, or added in later versions? Why not keep Pi a symbolic and with evalf it gives numerical value as with Mathematica? Also, would one use pi? It if just symbol (evalf(pi)) does nothing, then what is its use? if I can see a good use for pi vs. Pi, may be I'll understand the logic behind this duel system.