I am trying to figure out how to plot a centrifugal pump performance curve in mathcad prime 3.1. I have defined all the variables and reduced the pump head equation so that it is dependent only on the volume flowrate. It is gas flowing through the system and i want to see the performance curve for volume flowrates between 0 and 500 gpm. When i try to plot the function it does not do it and instead i get an error on the plot box saying "Plotting failed. Replace complex values and NaNs by real numbers." None of the values i am dealing with is complex and there are no square roots to make it complex. Whats even stranger is i have defined the head pump as function of flowrate and when plugging in values for the flowrate i get correct answers (e.g. h(300 gpm)=1169 ft.). So why is it not plotting the function though? I attached my mathcad file so you can see what i am talking about.
