Polynomial operations with np.poly in NumPy - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a polynomial from roots using np.poly.

NumPy

import numpy as np
roots = [1, 2, 3]
poly_coeffs = np.[1](roots)
print(poly_coeffs)

Drag options to blanks, or click blank then click option'

Apoly

Bpoly1d

Croots

Dpolyfit

Attempts:

3 left

💡 Hint

Common Mistakes

Using np.poly1d instead of np.poly, which creates a polynomial object, not coefficients.

Using np.roots which finds roots from coefficients, not the other way around.

The np.poly function returns the coefficients of the polynomial with the given roots.

2fill in blank

medium

Complete the code to evaluate the polynomial at x=2 using np.polyval.

NumPy

import numpy as np
coeffs = [1, -6, 11, -6]  # coefficients for (x-1)(x-2)(x-3)
value = np.[1](coeffs, 2)
print(value)

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Apolyval

Broots

Cpoly

Dpolyfit

Attempts:

3 left

💡 Hint

Common Mistakes

Using np.poly which returns coefficients, not evaluation.

Using np.roots which finds roots, not evaluates.

The np.polyval function evaluates a polynomial at given points.

3fill in blank

hard

Fix the error in the code to multiply two polynomials using np.polymul.

NumPy

import numpy as np
p1 = [1, -1]  # x - 1
p2 = [1, -2]  # x - 2
product = np.[1](p1, p2)
print(product)

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Apolyval

Bpolyfit

Cpolyadd

Dpolymul

Attempts:

3 left

💡 Hint

Common Mistakes

Using np.polyadd which adds polynomials instead of multiplying.

Using np.polyval which evaluates polynomials, not multiply.

The np.polymul function multiplies two polynomials represented by their coefficients.

4fill in blank

hard

Fill both blanks to create a polynomial from roots and then find its roots.

NumPy

import numpy as np
roots = [4, 5, 6]
coeffs = np.[1](roots)
found_roots = np.[2](coeffs)
print(found_roots)

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Apoly

Bpolyval

Croots

Dpolyfit

Attempts:

3 left

💡 Hint

Common Mistakes

Using np.polyval instead of np.roots to find roots.

Using np.polyfit which fits data, not related here.

First, np.poly creates polynomial coefficients from roots. Then, np.roots finds roots from coefficients.

5fill in blank

hard

Fill all three blanks to create a polynomial from roots, evaluate it at x=3, and multiply by another polynomial.

NumPy

import numpy as np
roots = [1, 2]
p1 = np.[1](roots)
val = np.[2](p1, 3)
p2 = [1, -3]
product = np.[3](p1, p2)
print(val)
print(product)

Drag options to blanks, or click blank then click option'

Apoly

Bpolyval

Cpolymul

Droots

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up np.roots with np.polyval.

Using np.polyfit which is for fitting data, not polynomial operations.

Use np.poly to get coefficients from roots, np.polyval to evaluate the polynomial at 3, and np.polymul to multiply polynomials.