% Derivative of test function #1 for Exercise 8.8

function y = fct(x)
  y = 8*x.^7 - 7*8*x.^6 + 6*28*x.^5 - 5*56*x.^4 + 4*70*x.^3 - 3*56*x.^2 +2*28*x - 8;