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Appendix B: Lagrangian
Interpolation in a Table
When it is required to obtain a value for a parameter from a set of tables, it is often
found that the tables do not contain the data pair corresponding to the required val-
ues. For instance, if a value is required for parameter y corresponding to the value
x= 2.5 and the table contains x values of integers such as 0, 1, 2, 3, 4, etc., and the y
values corresponding to these x values, an interpolation must be made for the y value
between the values corresponding to x = 2 and x = 3. In this case, it is useful to use
the method proposed by Lagrange, known as Lagrangian interpolation, to obta