Solve

The solve key is not programmable, but it is a powerful addition to the calculator functionality. The solve function utilizes HP Solve, a feature unique to HP calculators, which allows you to find a number for a variable that will cause a program to return a 0. This can be used to solve complex equations.

For example, if you want to solve xx-y=0.

1.:E<<I(select and edit program 2)

2.L1:hL1-L2= (HOLD)

(enter program var1var1 -var2=)

3.Press Oto exit. Store 3 into variable 2 by pressing 3:$1. Press :Eand note that Prgrm 2 is selected, as the calculator displays the program that was last edited. For verification, this program has 11 bytes, and the checksum, 199.

4.Press :(HOLD) 2to solve for variable 2. The calculator will attempt to

find what value in variable 2 would cause the program to result in 0. In this case, the result is 27.

5.Now store 10 into variable 2: 10:$2. Since Prgrm 2 was the last program selected in the program menu, you can use the SOLVE feature directly. Press

:(HOLD) 1to solve for variable 1, such that the result of the program is 0. The result this time is 2.506184..., since you stored 10 into variable 2.

6.You can verify this is correct by pressing L1:hL1=and see that 10 is returned.

Programming 87