Roulette (curve) in this case, the point lies on the circle then the roulette is a cycloid. A related concept is a glissette, the curve described by a point attached to a given curve as it slides along two (or more) given curves. Formally speaking, the curves must be differentiable curves in the Euclidean plane. The "fixed curve" is kept invariant; the "rolling curve" is subjected to a continuous congruence transformation such that at all times the curves are tangent at a point of contact that moves with the same speed when taken along either curve (another way to express this constraint
Grading on a curve Grading on a curve In education, marking on a curve (BE) or grading on a curve (AE, CE) (also referred to as curved grading, bell curving, or using grading curves) is a method of assigning grades to the students in a class in such a way as to obtain a pre-specified distribution of these grades, such as a normal distribution (also called Gaussian distribution). The term "curve" refers to the bell curve, the graphical representation of the probability density of the normal distribution, but this method can be used to achieve any desired distribution of the grades – for example,