I'm working on an equation for a wine glass that holds 150 ml. The actual equation I found for the cup is -20cos((pi/4)x) + 40, and the limits of integration I used to find the volume were 0 to 8.14818. Now, I am having trouble making an equation for a stem for this cup. The stem doesn't need to equal any volume, but it has to be a reasonable to the shape of the cup. Could someone please help me find an equation for the stem?