Bernstein Polynomial Calculator

C(n,k)·t^k·(1-t)^{n-k}

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About Bernstein Polynomial Calculator

A Bernstein polynomial calculator computing B_{k,n}(t) = C(n,k)·t^k·(1-t)^{n-k}. Bernstein polynomials form a basis for polynomials on [0,1]. They define Bézier curves: B(t) = Σ P_k·B_{k,n}(t). Used in CAD, font design, animation. Client-side.

Bernstein Polynomial Calculator Features

  • B_{k,n}(t) value
  • All basis functions
  • Partition of unity
  • Bézier connection
  • Degree elevation
Bernstein polynomials: B_{k,n}(t)=C(n,k)t^k(1-t)^{n-k}, k=0,...,n. Key properties: non-negative on [0,1], partition of unity (sum=1), and form a basis. Bézier curves: B(t)=Σ P_k·B_{k,n}(t). Weierstrass approximation theorem proof uses Bernstein polynomials.

How to Use

Enter n and t:

  • Values: All B_{k,n}(t)
  • Verify: Sum = 1
  • Bézier: Curve evaluation

Bézier Curves

Control points P_0,...,P_n define a Bézier curve: B(t)=Σ P_k·B_{k,n}(t). Degree 3 (cubic) is most common: B(t)=(1-t)³P₀+3t(1-t)²P₁+3t²(1-t)P₂+t³P₃. Used in PostScript, TrueType fonts, SVG paths.

Special Properties

Non-negativity: B_{k,n}≥0 on [0,1]. Partition of unity: Σ_k B_{k,n}=1. Symmetry: B_{k,n}(t)=B_{n-k,n}(1-t). Maximum at t=k/n with value C(n,k)(k/n)^k((n-k)/n)^{n-k}.

Step-by-Step Instructions

  1. 1Enter degree n.
  2. 2Enter parameter t.
  3. 3Compute all B_{k,n}(t).
  4. 4Verify sum = 1.
  5. 5See Bézier link.

Bernstein Polynomial Calculator — Frequently Asked Questions

Why are Bernstein polynomials used for Bézier curves?+

Non-negativity + partition of unity = the curve lies in the convex hull of control points. This gives geometric intuition: moving a control point predictably changes the curve. No other polynomial basis has this property.

How does Bernstein relate to Weierstrass theorem?+

The Bernstein polynomial of f is B_n(f;t)=Σf(k/n)B_{k,n}(t). Bernstein proved B_n(f)→f uniformly on [0,1] for continuous f. This gives a constructive proof of the Weierstrass approximation theorem.

What is degree elevation?+

A degree-n Bézier curve can be exactly represented as degree-(n+1) with new control points: P'_k = (k/(n+1))P_{k-1} + (1-k/(n+1))P_k. This adds control without changing the curve. Essential for matching degrees in CAD operations.

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