# HP Prime for All

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arcLen(Expr, Real1, Real2)

Returns the length of the arc of a curve between two points on the curve. The curve is an expression, the independent variable is declared, and the two points are defined by values of the independent variable.
This command can also accept a parametric definition of a curve. In this case, the expression is a list of 2 expressions (the first for x and the second for y) in terms of a third independent variable.

arcLen(x^2, x, -2, 2) returns 9.29….
arcLen({sin(t), cos(t)}, t, 0, π/2) returns 1.57…