Curve Sketching Calculator | Critical Points & Inflection Points

Curve Sketching Tool (Critical & Inflection Points)

High School Curve Sketching Tool

Identify Critical Points (Maxima/Minima) and Inflection Points to sketch graphs accurately.

Try: x^3 – 3x, x^4 – 4x^2, sin(x)

Calculated Derivatives

f'(x) =

f”(x) =

Features Found

Ready to analyze…

Curve Graph

Maxima
Minima
Inflection Pt

Using the Curve Sketching Tool

Curve sketching is a methodical process used in calculus to draw the graph of a function by analyzing its properties without plotting thousands of points manually. This Curve Sketching Tool automates the calculus steps to reveal the “interesting” parts of the graph: the peaks, valleys, and twists.

Critical Points (f'(x) = 0)

The first derivative, f'(x), represents the slope of the tangent line.

  • Local Maximum: Occurs where the slope changes from positive to negative (top of a hill).
  • Local Minimum: Occurs where the slope changes from negative to positive (bottom of a valley).

Inflection Points (f”(x) = 0)

The second derivative, f”(x), measures concavity (how the curve bends).

  • Concave Up (Smile): f”(x) > 0. The curve holds water.
  • Concave Down (Frown): f”(x) < 0. The curve spills water.
  • Point of Inflection: A point where the concavity changes (e.g., from up to down). This happens where f”(x) = 0 (and changes sign).

Why use a Curve Sketching Tool?

Manual calculations involving the second derivative test or solving cubic equations for roots can be lengthy and error-prone. This tool provides instant verification, allowing you to focus on understanding the relationship between the algebraic derivatives and the geometric shape of the curve.

FAQ

Is this Curve Sketching Tool free?

Yes, this resource is completely free for students and teachers.

What is the Second Derivative Test?

It’s a method to classify critical points. If f'(c) = 0, then f”(c) > 0 implies a Minimum, and f”(c) < 0 implies a Maximum.

Does the Curve Sketching Tool find asymptotes?

This version focuses on Critical Points and Inflection Points. Vertical asymptotes may appear as steep lines if the function is undefined at certain points (like 1/x at x=0).

Why isn’t my inflection point showing?

An inflection point requires a change in concavity. Simply having f”(x) = 0 isn’t enough (e.g., y = x^4 at x=0 is flat but not an inflection point).

HIGHER SCHOOL