HP35s: Interpolate

[ChristianB.]

Hi,

just got my 35s (78,- EUR incl. shipping from dynatech.de), seems to be a nice piece of hardware. But anyway....

I often do interpolation. On my 49g+ it was an easy programm with 5 values in the stack. The RPN programm was:

<< -> A B C D E '(D-B)/(C-A)*(E-A)+B' >>

If have no good idea how to do it on my 35s. Do have to use 5 (!) Labels for the variables and anotherone for the programme, or is there another (better) way?

How would you do it?

Regards from Hamburg !!

ChristianB

[Thomas Radtke]

If you have to keep the content of the named variables, you should make yourself familiar with *indirect addressing* (Page 14-20 in the english manual). There's plenty of space in the 35s accessible this way.

[Meenzer]

Put

(D-B)/(C-A)*(E-A)+B

in an EQN. Run the EQN by pressing XEQ when you have chosen it and you'll be prompted for the 5 values A to E (each only once, not twice in the case of A or B). No need for a program at all.

Edited: 18 Dec 2007, 11:11 a.m.

[Brad Davis]

LOL, I had a similar program on my 48G. I only had about 3 programs and this was one of them.

On my 35s, I use linear regression to do this and it is very fast--probably faster than finding and running my program on my 48G.

Clear the stat data, enter the two known x,y pairs, enter the known x and hit L.R. You should see your unknown y value.