My first newbie WP 34S question

[Dieter]

(06-04-2015 01:03 AM)Marcio Wrote:  Dieter, have you ever compared them in terms of abilities to find roots? Has the solver of the 35s ever failed you?

As much as I like the 34s, I think there is no doubt that HP's solver algorithm is far more sophisticated. I never had any problems, and if there is a root I cannot remember the 35s (or earlier the good old 34C) was not able find it – provided you start with two reasonable guesses.

The 35s solver is also able to solve equations symbolically. This can be done in equation mode (which IMHO is an advantage on its own).

Example: flash photography
D = flash distance, G = nominal (ISO 100) guide number, I = ISO speed, A = aperture

Code:

 D=G*SQRT(I/100)/A

Assume your flash has GN 30 and you want to illuminate a subject at 20 m distance while your lens provides a maximum aperture of f/4. Which ISO setting is required?

Code:

SOLVE I
D?  20 R/S
G?  30 R/S
A?  4  R/S
I=  711,1111

So ISO 800 (next higher setting) is fine.

The result appears immediately without iteration or any guesses. The 35s internally rearranges the equation to I = 100*(D*A/G)² and calculates the solution directly.

Dieter