i just bought a ti 92 very nice but can't figure out how to gragh a step function. i down loaded a program called pcewise() that are able to graph these type of equation but i can't figure out how to use it. i want to graph this equation: v(t)= 2(t)*u(t)- 2(t-2)*u(t-2)- (t-4)*u(t-4)+ (t-6) *u(t-6) could somebody show me how to graph this thank in advance