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The California Job Case was a compartmentalized box for printing in the 19th century, sizes corresponding to the commonality of letters. The frequency of letters in text has been studied for use in cryptanalysis, and frequency analysis in particular, dating back to the Arab mathematician al-Kindi (c. AD 801–873 ), who formally developed the method (the ciphers breakable by this technique go ...
A little algebra shows that the distance between P and M (which is the same as the orthogonal distance between P and the line L) (¯) is equal to the standard deviation of the vector (x 1, x 2, x 3), multiplied by the square root of the number of dimensions of the vector (3 in this case).
In probability theory, the Fourier transform of the probability distribution of a real-valued random variable is closely connected to the characteristic function of that variable, which is defined as the expected value of , as a function of the real variable (the frequency parameter of the Fourier transform).
Analysis is further subdivided into real analysis, where variables represent real numbers, and complex analysis, where variables represent complex numbers. Analysis includes many subareas shared by other areas of mathematics which include: [14] Multivariable calculus; Functional analysis, where variables represent varying functions
A percentage change is a way to express a change in a variable. It represents the relative change between the old value and the new one. [6]For example, if a house is worth $100,000 today and the year after its value goes up to $110,000, the percentage change of its value can be expressed as = = %.
According to Newton's law of universal gravitation, the magnitude of the attractive force (F) between two bodies each with a spherically symmetric density distribution is directly proportional to the product of their masses, m 1 and m 2, and inversely proportional to the square of the distance, r, directed along the line connecting their centres of mass: =.
Thus, for the whole Earth (which has a cross section of 127,400,000 km 2), the power is 1.730×10 17 W (or 173,000 terawatts), [9] plus or minus 3.5% (half the approximately 6.9% annual range). The solar constant does not remain constant over long periods of time (see Solar variation ), but over a year the solar constant varies much less than ...
N i is the expected number of particles in the single-particle microstate i, N is the total number of particles in the system, E i is the energy of microstate i, the sum over index j takes into account all microstates, T is the equilibrium temperature of the system, k B is the Boltzmann constant.