Question

I am new to matlab and do not know how to make a table that compares the values of this polynomial function with w=1/(x^2+1)

my attempt

 x= [-5,-3,-1, 1, 3,5]

 x =

-5    -3    -1     1     3     5

y= [0.0385, 0.10, 0.50, 0.50, 0.10, 0.0385]

y =

0.0385    0.1000    0.5000    0.5000    0.1000    0.0385

yp=[0.0148,0.06,0.50,-0.50,-0.6,-0.0148]

yp =

0.0148    0.0600    0.5000   -0.5000   -0.6000   -0.0148

hp = hermite (x, y, yp )

hp =

-0.0000   -0.0000    0.0001    0.0004   -0.0011   -0.0100    0.0072    0.0969   -0.0113   -0.4156    0.0051    0.8282

Now it only remains to compare in a table the values of hp with w.

Could someone please help me?

Thanks for your help

Answer 1

I see no w in your question, but in general the expression

hp == w

will, if the vectors have the same length, return a vector of 0s and 1s, of that length, representing the cases where the two vectors match (1) or don’t match (0). In passing, note that comparison for equality of floating-point numbers is fraught with ‘issues’ and you might be better evaluating:

abs(hp-w) < 10^-6

replacing 10^-6 by your preferred tolerance.

Given your definition for w you should be able to write

hp == 1/(x.^2+1)

Note the use of the elementwise squaring operator .^, which returns a vector of the same length as x with each element the square of the corresponding element in x. Of course, the expression

hp - 1./(x.^2+1)

will return a vector of the differences, which might be what you want.