PPT Slide
This is obtained by finding the function values
f(x0) = exp(-1) = 0.36787944,
f(x1) = exp(-1/3)= 0.71653131,
f(x2) = exp(1/3)=1.39561234,
f(x3) = exp(1) = 2.71828183,
and using the coefficient polynomials to the linear combination.
P(x) = 0.36787944 L3,0(x) + 0.71653131 L3,1(x) + +1.39561234 L3,2(x) + 2.71828183 L3,3(x)