RemoveProperty[{obj, item}] removes all properties associated with item in obj.RemoveProperty[{obj, item}, name] removes the property name associated with item in obj.

Re[z] gives the real part of the complex number z.

RescalingTransform[{{x_min, x_max}, {y_min, y_max}, ...}, {{xp_min, xp_max}, ...}] gives a TransformationFunction that rescales the region with coordinate ranges x_min to ...

RGBColor[red, green, blue] is a graphics directive specifying that objects that follow are to be displayed, if possible, in the color given. RGBColor[r, g, b, a] specifies ...

Riffle[{e_1, e_2, ...}, x] gives {e_1, x, e_2, x, ...}. Riffle[{e_1, e_2, ...}, {x_1, x_2, ...}] gives {e_1, x_1, e_2, x_2, ...}. Riffle[list, x, n] yields a list in which ...

RootIntervals[{poly_1, poly_2, ...}] gives a list of isolating intervals for the real roots of any of the poly_i, together with a list of which polynomials actually have each ...

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

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

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, ...

RuntimeOptions is an option for Compile that specifies runtime settings for the compiled function it creates.