HP 30b Programming

[lrdheat]

The program that I gave was for a function that cannot produce a result for the -2 and +2 roots as they occur where a change of sign indicating a root in between is an impossibility due to square root of a negative number results for x<-2, x>+2.

Here is a program to find roots of x^3 -5*x^2 -2x/7

RCL 1
3
Y^X
RCL 1
X^2
5
*
-
RCL 1
2
*
7
/
-
RCL 2
-
Stop

Since I am looking for f(x)=0, I store 0 in register 2.

Find the 3 roots:

Storing guess “1” of -.1 to register 1, solve variable 1 instantly produces the root near -.057

Storing guess “2” of 1 to register 1, solve variable 1 instantly produces the root of 0

Storing guess “3” of 4 to register 1, solve variable 1 instantly produces the root near 5.057