RootOfUnityQ[a] yields True if a is a root of unity, and yields False otherwise.

RootReduce[expr] attempts to reduce expr to a single Root object.

Roots[lhs == rhs, var] yields a disjunction of equations which represent the roots of a polynomial equation.

RootSum[f, form] represents the sum of form[x] for all x that satisfy the polynomial equation f[x] == 0.

RotateLabel is an option for graphics and related functions that specifies whether labels on vertical frame axes should be rotated to be vertical.

RotateLeft[expr, n] cycles the elements in expr n positions to the left. RotateLeft[expr] cycles one position to the left. RotateLeft[expr, {n_1, n_2, ...}] cycles elements ...

Rotate[g, \[Theta]] represents 2D graphics primitives or any other objects g rotated counterclockwise by \[Theta] radians about the center of their bounding box. Rotate[g, ...

RotateRight[expr, n] cycles the elements in expr n positions to the right. RotateRight[expr] cycles one position to the right. RotateRight[expr, {n_1, n_2, ...}] cycles ...

RotationAction is an option for three-dimensional graphics functions that specifies how to render 3D objects when they are interactively rotated.

RotationMatrix[\[Theta]] gives the 2D rotation matrix that rotates 2D vectors counterclockwise by \[Theta] radians.RotationMatrix[\[Theta], w] gives the 3D rotation matrix ...