HP 41 Polar Plots?
12-21-2013, 08:41 PM (This post was last modified: 12-21-2013 09:02 PM by mbrethen.)
Post: #1
 mbrethen Junior Member Posts: 40 Joined: Dec 2013
HP 41 Polar Plots?
Anyone know if it's possible to plot f(r,theta) using an hp 41 and 82240 printer? For example:

R(theta) = 1/2 + 3/4*sin^2(theta) + 1/2*cos(theta)

describes the approximate plastic zone shape (normalized) ahead of a crack tip. Below is the solution in r, theta, x, y from 0< theta < 180 deg.

Code:
 R            θ       x            y 1.00E+00    0       1.00E+00    0.00E+00 1.03E+00    15      9.98E-01    2.67E-01 1.12E+00    30      9.70E-01    5.60E-01 1.23E+00    45      8.69E-01    8.69E-01 1.31E+00    60      6.56E-01    1.14E+00 1.33E+00    75      3.44E-01    1.28E+00 1.25E+00    90      7.66E-17    1.25E+00 1.07E+00    105    -2.77E-01    1.03E+00 8.13E-01    120    -4.06E-01    7.04E-01 5.21E-01    135    -3.69E-01    3.69E-01 2.54E-01    150    -2.20E-01    1.27E-01 6.73E-02    165    -6.50E-02    1.74E-02 0.00E+00    180     0.00E+00    0.00E+00

Ideally, you'd sort the x, y values to get the correct shape. I thought about writing a subroutine to do this using either "regplot" or "stkplot". Note there a two solutions at x = 0.
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 Messages In This Thread HP 41 Polar Plots? - mbrethen - 12-21-2013 08:41 PM RE: HP 41 Polar Plots? - SlideRule - 12-21-2013, 11:08 PM RE: HP 41 Polar Plots? - Ángel Martin - 12-22-2013, 08:12 AM

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