My HP 10bII+ is much faster than HP 12c!

[ijabbott]

(01-06-2020 01:04 AM)Albert Chan Wrote:  My guess so many calculators failed this is because we have multiple solutions.
For my posted example, we have 2 (real) solutions for I.

Using HP-12C IRR (with the good guess), it did solve them.

Clear Reg
1000 CF0      ; PV
CHS CFj        ; PMT
29 Nj            ; N-1
49000 CFj     ; FV + last payment

IRR                             → Error 3
3 [i] RCL [g] [R/S]       → 3.651974353
100 [i] RCL [g] [R/S]    → 99.99999525

Same thing for HP 17BII+:

[FIN] [CFLO]
[SHIFT] [CLR DATA] [YES]
"FLOW(0)=?" 1000
"FLOW(1)=?" -1000
"#TIMES(1)=1" 29
"FLOW(2)=?" 49000
"#TIMES(2)=1"
[EXIT]
[CALC]
0 [STO] [IRR%] → 3.65197435259
100 [STO] [IRR%] → 99.9999952503