3. (Science: mathematics) opposite in nature and effect; said with reference to any two operations, which, when both are performed in succession upon any quantity, reproduce that quantity; as, multiplication is the inverse operation to division. The symbol of an inverse operation is the symbol of the direct operation with -1 as an index. Thus sin -1 x means the arc whose sine is x.
(Science: geometry) inverse figures, two points lying on a line drawn from the center of a fixed circle or sphere, and so related that the product of their distances from the center of the circle or sphere is equal to the square of the radius.
(Science: mathematics) inverse, or reciprocal, ratio, the ratio of the reciprocals of two quantities. Inverse, or reciprocal, proportion, an equality between a direct ratio and a reciprocal ratio; thus, 4: 2:: 1/3: 1/6, or 4: 2:: 3: 6, inversely.