Here's the question you clicked on:
windsylph
Signals and Systems: Causality: Can someone please explain how y(t) = ((t-1)^3)x(t/2) is a causal system? I see no way how y(t) uses future values of x(t)...
Remember that t/2 <= t, so it is a causal system, because it relies on *past*, not future, values of x(t).
oh gosh I messed up my definition of "causal"... thanks!
Wait, nvm, I wanted to ask why this is NOT causal. I was marked off in my exam for saying it is causal because it doesn't use future values of x(t). Or maybe this is just a grading mistake..
I'm pretty sure your statement is right, though, but I may be wrong...? Dunno, I'd go check with your prof, just in case.