Calculatrice 3D

A graph you can turn with your finger says more than a still picture. Drag to rotate the surface, pinch to grow it, tap a sheet to select it. A LAYOUT PER SCREEN On iPad, three columns: modules on the left, their settings in the middle, the graph on the right — and the calculator in its own window for anyone who wants it beside other work. On iPhone, the surface keeps the top of the screen and the modules scroll underneath, so you watch the sheet change while you adjust it. Held sideways, the phone splits the width rather than the height, and one button gives the graph the whole screen. WRITE IT AS YOU WOULD ON PAPER 2x, xy, (x+1)(x−1), |x|, √x, x², sin x: the parser takes handwritten notation, with no need for polite brackets. Polar coordinates r and θ are provided, and the variable t sets the surface in motion. READ THE SURFACE The probe goes wherever you want it, on the two sliders in the Tools tab, and gives you the value, both partial derivatives, the gradient norm, the slope in degrees, Gaussian curvature, mean curvature and the equation of the tangent plane. Derivatives are exact — symbolic differentiation, not finite differences — whenever the expression allows it, and the app tells you which of the two it used. THREE WAYS TO WRITE A SURFACE The graph z = f(x, y). The parametric surface P(u, v) — sphere, torus, Möbius strip, Klein bottle: seventeen examples. The implicit surface F(x, y, z) = c, extracted by marching tetrahedra — gyroid, tanglecube, pretzel, heart: fifteen examples, the closed ones checked against their Euler characteristic. ANALYSE Cross-sections at constant x or y, with the resulting curve and its length. Critical points sorted by nature. Integrals over a disc, a rectangle, an annulus. Taylor expansion laid over the sheet. Gradient descent drawn on the surface. Vector field. Intersection of two sheets. COMPUTE Equation roots, statistics and regression, least-squares surface fitting, matrix algebra, thirteen families of units and twenty physical constants. AND A REAL CALCULATOR Three keypads — Simple, Scientific, and Engineer with its 65 keys — three skins, a history, memory, degrees, radians and gradians. A hardware keyboard and dictation work too: anything you can write, it evaluates. IN CLASS During a FaceTime call, the same surface appears for every participant. It is the equations that travel, not the picture: everyone keeps their own viewpoint and display quality. Joining a session is free, and will stay free — a class where only the pupils who paid can see the board is no class at all. PRINT The active surface exports as binary STL or OBJ, resampled, recentred and scaled in millimetres: the file goes straight to your slicer. FOUR LANGUAGES French, English, Spanish, Chinese — switched without leaving the app, mid-lesson if need be. WHAT IS FREE Plotting z = f(x, y), the probe, the tangent plane, cross-sections, critical points, integrals, the scientific calculator with its first two keypads, joining a shared session, all four languages and every function example. WHAT UNLOCKS Parametric and implicit surfaces, the Compute tab, optimisation tools, STL and OBJ export, the Engineer keypad. One purchase, no subscription, valid on Apple Vision Pro and Mac too with the same Apple Account. Family Sharing enabled, and volume purchase available to schools.