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prime:polrec [2017/10/16 20:39]
prime:polrec [2017/12/15 03:40] (current)
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 +====== Polar/​Rectangular ======
 +Polar coordinates are entered using R∠Angle, where ∠ is Shift-x (multiply).
 +Rectangular coordinates are entered using complex values as in a+b*i (where i is Shift-2). Also useful is the π symbol (shift-3).
 +You can convert angles between radians and degrees by using the Shift-Units menus. From the tools menu, the CONVERT function does the conversion. Then you can select (rad) or (deg) from the Units-Angle menu. So, use CONVERT(1.5_(rad),​1_(deg)) to convert 1.5 radians to degrees. You do have to enter the 1 in 1_(deg). Note that other angle formats are also available in Units-Angle.
 +In the geometry app you can enter a point in either form using the point() function.
 +If you enter a polar coordinate as in 1∠(π/4), and hit enter, and then hit the ∠ button again, it'll convert the number to it's rectangular/​complex form.
 +When using negative angles, be sure to use the +/- key rather than the - key.
 +Note that if your system is set to radians by default, you can enter degrees by using shift-units and from the units menu, select angle-deg and the value will appear as 30_deg for example.
 +if you type 1∠30_deg and hit enter, it'll convert automatically to 1∠0.5325... (radians).
 +To enter a point this way in the geometry app, you cannot enter point(1∠30_deg),​ but you can enter 1∠30 on the home view and hit enter to convert to radians. Then, in the geometry app, you can enter point() and select menu-copy_from_home and select the radian version to put it in the point call. You can alternatively enter point(EXPR("​1∠30_deg"​)).
 +The following function is a useful one to have in your arsenal. It will convert from polar to rectangular and vice versa...automatically. It must be run from Home mode.
 + ​T:​=STRING(Z);​
 +  // POLAR
 +  A:=RE(Z);
 +  B:=IM(Z);
 +  RETURN EXPR(A "​+"​ B*i);
 +  A:=ABS(Z);
 +  B:=ARG(Z);
 +  RETURN EXPR(A "​∠"​ B);
 + END // IF...