- #36
Integral
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franznietzsche said:if you had told me those keystrokes, even knowing what RPN is, i would i have no idea what you just plugged in.
# represents a number (ie key in a number, in this case the each # is a different component of the coordinates.
(enter) = hit the enter key
# the next coordinate
- = hit the minus key (this gives the difference of the 2 #s)
(enter) push the result onto the stack
* = hit the multiply key (compute the square)
# (key in another coordinate)
Enter
# (key in another coordinate)
- compute the difference
Enter
* (compute the square)
+
Add em up
(Sqrt) yields the distance.
To use RPN you have to understand the stack, the modern calcs show several levels of the stack on the screen and the only limitation is calculator memory, this is very helpful. Back in the old days (I started with a HP35 in 1973) you only saw the x register and had to keep track of the stack (only 4 levels) for yourself. That can be tricky.
A neat trick for evaluating polynomials on any calculator is attributed to someone called Hooker.
Basicly you factor the polynomial eg,
[tex] x^2 + 3x +5 = x(x+3)+5 [/tex]
To evaluate this at x = 4
key:
4
enter
enter
3
+
*
5
+
Can you do it in fewer key strokes on your TI?