EasyCalculusca-013

Normal Line Slope

Problem

Return the slope of the line normal to f(x) = sum(coeffs[i] * x^i) at x0.

The normal slope is -1 / f'(x0). If f'(x0) == 0 the normal is vertical and the function returns None.

Hint

Perpendicular slopes multiply to -1, so take the negative reciprocal.

case 1

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

expected: -0.25

case 2

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

expected: -0.5

case 3

in: [[5],1]

expected: null

case 4

in: [[0,3],4]

expected: -0.3333333333333333

Starter codePython

def normal_slope(coeffs, x0):
    # Return None when f'(x0) == 0
    # Your code here
    pass

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