Knee of a curve

Shape in mathematics

In mathematics, a knee of a curve is a point where the curve visibly bends, specifically from high slope to low slope, or in the other direction. This is particularly used in optimization, where a knee point is the optimum point for some decision, for example when there is an increasing function and a trade-off between the benefit and the cost : the knee is where the benefit is no longer increasing rapidly, and is no longer worth the cost of further increases – a cutoff point of diminishing returns.

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