# Interpolation

• October 13th 2009, 10:02 PM
jzellt
Interpolation
a) Find the function P(x) = a + bcos(pi x) + csin(pi x) which interpolates the data
x | 0 0.5 1
y | 2 5 4

b) Find the quadratic plynomial interpolating this data

• October 13th 2009, 11:20 PM
CaptainBlack
Quote:

Originally Posted by jzellt
a) Find the function P(x) = a + bcos(pi x) + csin(pi x) which interpolates the data
x | 0 0.5 1
y | 2 5 4

At a minimum plugging the data into the interpolating form will give you three simultaneous linear equations in three unknowns which you should be able to solve.

For the first point this gives:

$2=a+b \cos(0) + c \sin(0)$

or:

$2=a+b$

CB