Lagrangian Interpolation

[PedroLeiva]

I think I was asking HP25 too much. Anyway, I found that the example of the manual for linear interpolation works very well in both cases………….
Example from HP 25 Application Programs, Chapter 5 Numerical Methods/Linear Interpolation: p86
Given
f(7.3)= 1.9879
f(7.4)= 2.0015
find by linear interpolation f(7.37)

A. CLEAR PRGM
R/S
1.0000
1.9879 ENTER 7.3
R/S
2.0000
2.0015 ENTER 7.4
R/S
3.0000
0 ENTER 7
[R/S]
CLx STO 5
7.37 [R/S]  1.9974

B. CLEAR PRGM
R/S
1.0000
1.9879 ENTER 7.3
R/S
2.0000
2.0015 ENTER 7.4
R/S
3.0000
1.9947 [ENTER] 7.35
[R/S]
7.37 [R/S]  1.9974

I appreciate your attention, Pedro