How to graph a function
- Type a function of x after y =, such as x^2 - 2, sin(x) or 2^x. Press Add a function (or Enter) to plot up to six in different colors.
- Drag the graph to move around, scroll or pinch to zoom, or use the + and − buttons. Arrow keys pan and + / − zoom when the graph has focus.
- Press and hold on a line, then drag along it to read its value at each x. Press a dot to read a root or intersection. All of them in view are listed under Roots and intersections.
Reading a graph
Where a curve crosses the x-axis is a root: a solution of f(x) = 0. Where two curves cross is a solution of f(x) = g(x), so graphing is a quick way to see how many solutions an equation has before solving it. Plot x² − 2 and the roots appear at ±1.414, which is ±√2.
The steepness of the curve at a point is its derivative and the area under it is its integral. The derivative calculator and integral calculator give those exactly or numerically.
Asymptotes and gaps
Functions like 1/x and tan(x) shoot off to infinity. The graph breaks the line at these jumps instead of drawing a false vertical stroke, and values outside a function’s domain (the square root of a negative number, the log of zero) are simply left blank.