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When a Secant Becomes a Tangent

by Anonymous · 0 · 🍴 0

Bring two points closer and watch the secant’s slope approach the tangent’s slope. Move it by hand from average rate of change to the derivative—and the derivative function.

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About this app

An interactive high-school calculus app that demonstrates how a secant line approaches a tangent as two points on a curve move closer together. Explore average rate of change, the derivative at a point, and the derivative function using three selectable functions: x²/2, x³/6 − 2x, and 3 − x²/2. Guided missions and adjustable controls help learners connect slope, tangent lines, and f′(x).

Use cases

  • High-school students learning differentiation
  • Teachers demonstrating secants and tangents
  • Self-study of average rate of change
  • Practice identifying positive, negative, and zero slopes

Features

  • Adjust the base point a and gap h for a secant line
  • Watch the secant slope approach the tangent slope
  • Explore tangent lines for three different functions
  • Move the tangency point and observe f′(a)
  • Compare a function f(x) with its derivative f′(x)
  • Complete guided missions with feedback