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The exponential of X, denoted by eX or exp (X), is the n×n matrix given by the power series. where is defined to be the identity matrix with the same dimensions as . [1] The series always converges, so the exponential of X is well-defined. Equivalently, where I is the n×n identity matrix. When X is an n×n diagonal matrix then exp (X) will be ...
Exponential may refer to any of several mathematical topics related to exponentiation, including: Exponential function, also: Matrix exponential, the matrix analogue to the above. Exponential decay, decrease at a rate proportional to value. Exponential discounting, a specific form of the discount function, used in the analysis of choice over time.
RGR is a concept relevant in cases where the increase in a state variable over time is proportional to the value of that state variable at the beginning of a time period. In terms of differential equations, if is the current size, and its growth rate, then relative growth rate is. . If the RGR is constant, i.e., , a solution to this equation is.
The power law of practice states that the logarithm of the reaction time for a particular task decreases linearly with the logarithm of the number of practice trials taken. It is an example of the learning curve effect on performance. It was first proposed as a psychological law by Snoddy (1928), [1] used by Crossman (1959) [2] in his study of ...
The graphs below show examples of hypothetical survival functions. The x-axis is time. The y-axis is the proportion of subjects surviving. The graphs show the probability that a subject will survive beyond time t. Four survival functions. For example, for survival function 1, the probability of surviving longer than t = 2 months is 0.37.
Exponential smoothing. Exponential smoothing or exponential moving average (EMA) is a rule of thumb technique for smoothing time series data using the exponential window function. Whereas in the simple moving average the past observations are weighted equally, exponential functions are used to assign exponentially decreasing weights over time.
Elementary function. In mathematics, an elementary function is a function of a single variable (typically real or complex) that is defined as taking sums, products, roots and compositions of finitely many polynomial, rational, trigonometric, hyperbolic, and exponential functions, including possibly their inverse functions (e.g., arcsin, log, or ...
In economics exponential discounting is a specific form of the discount function, used in the analysis of choice over time (with or without uncertainty ). Formally, exponential discounting occurs when total utility is given by. where ct is consumption at time t, is the exponential discount factor, and u is the instantaneous utility function .