HP -225 Owner's Manual page 92

Example: Area of a Polygon. The equation for the area of a regular
polygon with n sides of length d equals:
Area = 1 -
4 sin(w/n)
The equation is entered into the list of equations as:
A=NXD"2XCOSCA+NI+C4XSINCA+NI D
Calculate the area of a pentagon with equal sides 6 centimeters long.
Keys: Display: Description:
B(EQUATIONS]] Displays the equation
list.
If necessary, press [¥] until the HP-22S displays TYPE NEW E@HN.
Type the equation,* then:
N?value Prompts for N.
5 D?value Stores N, prompts for
D.
6 A=4,183.3434 Calculates the area.
* The keystrokes for typing the equation are A(=][(STOJN[x][(sTO] D [¥*] 2
B EHERINDEO4EN] @] EHETIND 0.
84 6: Evaluating and Solving Equations