ZeGrapher

ZeGrapher is a free and open-source plotting application focused on mathematical objects in the plane. Rather than a general-purpose graphing suite, it targets the everyday needs of people who want to visualize functions, sequences, parametric equations and data sets without a steep learning curve.

Its core strength is natural expression input: functions are written as you would on paper, such as f(x) = 2 + cos(x), with built-in mathematical functions plus user-defined objects. Sequences can be entered from their recurrence relation with initial terms, and parametric equations are drawn over a chosen interval. Constants and variables are shared across objects, so a single value can drive a family of curves, slide between bounds manually or as an animation, or hold several values at once.

Data support rounds out the feature set: CSV files can be imported and edited in a spreadsheet-like table, with testing on files of several million cells. Named objects can be reused in other expressions and in data columns, making layered models easier to build.

The tool suits students, teachers and hobbyists who need clear 2D graphs and exact exports of what is on screen. Beginners can start with simple functions, while more advanced users can combine shared constants, sequences and imported data. Overall, ZeGrapher is a lightweight, approachable option for everyday mathematical plotting.