HP 50g Graphing Calculator - Manual (Page 255)

Page 7-18
An explanation of the variables follows:
SOLVEP = a program that triggers the multiple equation solver for the
particular set of equations stored in variable PEQ;
NAME = a variable storing the name of the multiple equation solver, namely,
"vel. & acc. polar coord.";
LIST = a list of the variable used in the calculations, placed in the order we
want them to show up in the multiple equation solver environment;
PEQ = list of equations to be solved, corresponding to the radial and
transverse components of velocity (vr, v θ) and acceleration (ar, aθ)
in polar coordinates, as well as equations to calculate the
magnitude of the velocity (v) and the acceleration (a) when the
polar components are known.
r, rD, rDD = r (radial coordinate), r-dot (first derivative of r), r-double dot
(second derivative of r).
θD, θDD = θ-dot (first derivative of θ), θ-double dot (second derivative of θ).
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Suppose you are given the following information: r = 2.5, rD = 0.5, rDD = -
1.5,
θD = 2.3, θDD = -6.5, and you are asked to find vr, vθ, ar, aθ, v, and a.
Start the multiple equation solver by pressing J @SOLVE. The calculator
produces a screen labeled , "vel. & acc. polar coord.", that looks as follows:
To enter the values of the known variables, just type the value and press the
button corresponding to the variable to be entered. Use the following
keystrokes: 2.5 [ r ] 0.5 [ rD ] 1.5 \ [ rDD ] 2.3 [
θD ] 6.5 \ [ θDD ].