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Polynomial division and the remainder theorem

Long division, synthetic division, and why f(a) is the remainder on dividing by x − a.

Dividing polynomials works like long division of integers: divide the leading terms, multiply back, subtract, repeat. The remainder theorem says dividing f(x) by x − a leaves remainder f(a), so a is a root exactly when the division is clean. Picture it: the quotient's graph is the original with the root's factor removed. Think it: this is the Euclidean algorithm again, over polynomials instead of integers.

Eksempel på arbeid · simplify (x^3 - 1)/(x - 1)

Simplify (x^3 - 1)/(x - 1)

\frac{x^{3} - 1}{x - 1}

Steg for trinn

  1. \frac{x^{3} - 1}{x - 1}

    Start from the expression.

  2. x^{2} + x + 1

    Factor numerator and denominator and cancel common factors.

Vis svaret
x^{2} + x + 1

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Hvordan: Polynomial division and the remainder theorem

  1. Start from the expression.
  2. Factor numerator and denominator and cancel common factors.

Spørsmål folk stiller

What is a function, really?

A rule that assigns exactly one output to each input. The vertical-line test on a graph is the same idea: no input may have two outputs.

Why do we need complex numbers?

Because x² + 1 = 0 has no real solution, and allowing one new number i with i² = −1 makes every polynomial equation solvable. They then turn out to describe rotation, waves and alternating current more naturally than real numbers do.

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