Slopculator: calculator and grapher

Slopculator is a free calculator you type into, one line at a time. Each answer appears beside its line, and anything with an x is drawn on the graph. It needs JavaScript to run.

What it does

Exact answers. 0.1 + 0.2 is 3/10, sin(30°) is 1/2, and 2^64 keeps every digit.
Graphs with sliders. y = a(x − 1)^2 − 3 gets a slider for a. Zeros, extrema and intersections are marked.
Statistics and probability. normalcdf, invNorm, zscore, binompdf, t, χ² and F distributions, regressions, and a shaded normal curve.
Matrices and vectors. det, inverse, transpose and products, with an editor for typing them.
Calculus and algebra. Derivatives, integrals, sums, and solve(2^x = 10, x).
Units and engineering. convert(5, "mi", "km"), plus moist-air, duct and refrigerant functions for HVAC.

Typing math

Write it the way you would on paper: 2x, 3(4 + 5), sqrt 16, sin 30, |x|, 5!, 10% of 50, x². Missing closing brackets are filled in. Ctrl+K (⌘K on a Mac) finds any function by name or by what it does.