MediumCalculusca-024

Secant Method One Step

Problem

Take one secant-method step for f(x) = sum(coeffs[i] * x^i) using the two starting points x0 and x1:

x2 = x1 - f(x1) * (x1 - x0) / (f(x1) - f(x0))

If f(x1) == f(x0), return x1 unchanged.

Hint

The secant method replaces the derivative with a finite-difference slope.

case 1

in: [[-2,0,1],1,2]

expected: 1.3333333333333333

case 2

in: [[-2,-1,0,1],1,2]

expected: 1.3333333333333333

case 3

in: [[-1,0,1],0,1]

expected: 1

case 4

in: [[0,0,1],1,-1]

expected: -1

Starter codePython

def secant_step(coeffs, x0, x1):
    # Your code here
    pass

4 test cases · run your code against them in the editor