Radian symbol, and in mathematical writing the symbol "rad" is almost always omitted. When quantifying an angle in the absence of any symbol, radians are assumed, and when degrees are meant the symbol ° is used. It follows that the magnitude in radians of one complete revolution (360 degrees) is the length of the entire circumference divided by the radius, or , or 2. Thus 2 radians is equal to 360 degrees, meaning that one radian is equal to 180/ degrees. The relation formula_1 can be derived using the formula for arc length. Taking the formula for arc length, or formula_2.
Degrees of freedom (mechanics) rotation, which means that it has six degrees of freedom. The exact constraint mechanical design method manages the degrees of freedom to neither underconstrain nor overconstrain a device. The position of an "n"-dimensional rigid body is defined by the rigid transformation, ["T"] = ["A", "d"], where "d" is an "n"-dimensional translation and "A" is an "n" × "n" rotation matrix, which has "n" translational degrees of freedom and "n"("n" − 1)/2 rotational degrees of freedom. The number of rotational degrees of freedom comes from the dimension of the rotation group SO(n). A non-rigid or deformable body may be thought of