Drag to pan · Scroll to zoom
📏 Straight Line (y = mx + c)
- m = slope (rise ÷ run)
- c = y-intercept (where line crosses y-axis)
- m > 0 → line goes up · m < 0 → line goes down
- m = 0 → horizontal line · c = 0 → passes through origin
- Two lines intersect where their equations are equal
🎯 Quadratic (y = ax² + bx + c)
- a > 0 → parabola opens upward (∪)
- a < 0 → parabola opens downward (∩)
- Vertex x = −b / (2a)
- Axis of symmetry: x = −b / (2a)
- Discriminant b²−4ac: >0 two roots, =0 one root, <0 no real roots
🖱 How to use
- Pick a preset or click + Line / + Parabola / + Point
- Click a plot row to edit its equation and colour
- Drag the graph to pan, scroll to zoom
- 👁 button hides/shows a plot without deleting it
- Click ⬇ Download PNG to save the graph