Excel Interpolation

Question

I have the source data:

       35    40
-15    15.0  15.1
-10    17.2  17.4
-5     19.7  19.8

and I need to find the value in (-16, 37). I tried with linear interpolation, but I can only solve a pair (x, y). could you help me?

Thanks a lot Andrea

Answer 1

Thanks to everyone, your suggestions were very helpful for me to better understand the problem.

In the beginning, I posed the problem wrong, because I took a replica from the graphical representation of the data, the matrix. But after some “mumbling” :) I understand that the right way to introduce the problem is:

f (x1, x2) = y

       35    40
-15    15.0  15.1
-10    17.2  17.4
-5     19.7  19.8

so, i.e. f (35, -15) = 15.0

x1 = 37 x2 = -13, .

http://en.wikipedia.org/wiki/File:Bilinear_interpolation.png

.

!

Andrea

Answer 2

:

z=A*x+B*y+C

A, B, C, 6 (-15,35,15.0),... Excel .

Edit

( ) solver z = Ax + By + C. (x 35,40, y -15, -10, -5). A, B, C - . Ax + By + C, - ( ) ^ 2. - 6 .

Solver ( Excel). () A, B, C . A, B, C.

(x = 37 y = -16), 14.5.

Answer 3

, , , ( ), .

- excel, . , Enter. Ctrl + Shift + Enter. , , {} .

, , , @tom10,

=TREND(<known y's>,<known x's>,<new x's>)

y x.

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Answer 4

. .. -5 >= x >= -15. -16, .

- , , Ax = b) , , (-15, 37) - , , .

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Answer 5

, :

• x (, 35) 1D-, z- y- (-16), y z- . Z ₀.
• 1. x (40). Z ₁.
• ... y = -16, (35, Z ₀) (40, Z ₁), Z x-.

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Answer 6

, - 2D Excel, VBA . .

Answer 7

Interp2dTab xongrid