Tangent-line Visualizer
Draw a function and its tangent line. Move a point along the curve to see how the slope and line equation change.
How is the tangent slope calculated?
The tool differentiates the entered expression symbolically and evaluates that derivative at the selected x value. Move the point slider to update the graph, coordinates, slope, and tangent equation. Points outside the real-valued domain are rejected.
Your result
Explore the slope.
Choose a function and domain, then calculate to see the curve and tangent.
Three simple steps
How to use Tangent-line Visualizer
Choose your input and adjust the options.
Review the preview and run the tool.
Download the result and keep your original.
Common questions
Good to know
Understand the result.
Keep the original.
Is this tool free, and are my files uploaded?
This tool is free with no account required. The work happens in your browser. Your input and files are not sent to a processing server.
What are the limits and details?
Up to 800 sampled points per curve. The graph leaves gaps where the function is undefined. Large discontinuities may require a smaller domain. A tangent is unavailable where the function or derivative is not finite.
Limits: 500,000 characters per text field; files up to 20 MB each, 10 files and 50 MB total. Processing stops after 30 seconds.