# Logarithm sentence example

The calculation of a

**logarithm**can be performed by successive divisions; evolution requires special methods.In n = a P, a is the root or base, p is the index or

**logarithm**, and n is the power or antilogarithm.The work of Justus Byrgius is described in the article

**Logarithm**.But a P is sometimes incorrectly described as " a to the power p "; the power being thus confused with the index or

**logarithm**.The logarithms to base io of the first twelve numbers to 7 places of decimals are log 1 =0.0000000 log 5 log 2 = 0.3010300 log 6 log 3 =0.477 121 3 log 7 log 4 =0.6020600 log 8 The meaning of these results is that The integral part of a

**logarithm**is called the index or characteristic, and the fractional part the mantissa.AdvertisementThe fact that when the base is io the mantissa of the

**logarithm**is independent of the position of the decimal point in the number affords the chief reason for the choice of io as base.The explanation of this property of the base io is evident, for a change in the position of the decimal points amounts to multiplication or division by some power of 10, and this corresponds to the addition or subtraction of some integer in the case of the

**logarithm**, the mantissa therefore remaining intact.It should be mentioned that in most tables of trigonometrical functions, the number io is added to all the logarithms in the table in order to avoid the use of negative characteristics, so that the characteristic 9 denotes in reality 1, 8 denotes a, io denotes o, &c. Logarithms thus increased are frequently referred to for the sake of distinction as tabular logarithms, so that the tabular

**logarithm**=the true**logarithm**-IIo.In tables of logarithms of numbers to base io the mantissa only is in general tabulated, as the characteristic of the

**logarithm**of a number can always be written down at sight, the rule being that, if the number is greater than unity, the characteristic is less by unity than the number of digits in the integral portion of it, and that if the number is less than unity the characteristic is negative, and is greater by unity than the number of ciphers between the decimal point and the first significant figure.It follows very simply from the definition of a

**logarithm**that logo b X logo a, = 1, logo m =log.AdvertisementNapier's logarithms are not the logarithms now termed Napierian or hyperbolic, that is to say, logarithms to the base e where e= 2.7182818 ...; the relation between N (a sine) and L its

**logarithm**, as defined in the Canonis Descriptio, being N=10 7 e L/Ip7, so that (ignoring the factors re, the effect of which is to render sines and logarithms integral to 7 figures), the base is C".If 1 denotes the

**logarithm**to base e (that is, the so-called "Napierian " or hyperbolic**logarithm**) and L denotes, as above, " Napier's "**logarithm**, the connexion between 1 and L is expressed by L = r o 7 loge 10 7 - 10 7 / or e t = I 07e-L/Ia7 Napier's work (which will henceforth in this article be referred to as the Descriptio) immediately on its appearance in 1614 attracted the attention of perhaps the two most eminent English mathematicians then living - Edward Wright and Henry Briggs.It is important to notice that in the Constructio logarithms are called artificial numbers; and Robert Napier states that the work was composed several years (aliquot annos) before Napier had invented the name

**logarithm**.The " liber posthumus " was the Constructio (1619), in the preface to which Robert Napier states that he has added an appendix relating to another and more excellent species of logarithms, referred to by the inventor himself in the Rabdologia, and in which the

**logarithm**of unity is o.Briggs pointed out in his lectures at Gresham College that it would be more convenient that o should stand for the

**logarithm**of the whole sine as in the Descriptio, but that the**logarithm**of the tenth part of the whole sine should be Io,000,000,000.AdvertisementBut he considered that the change ought to be so made that o should be the

**logarithm**of unity and io,000,000,000 that of the whole sine, which.The name

**logarithm**is derived from the words X6 7 wv hp426s, the number of the ratios, and the way of regarding a**logarithm**which justifies the name may be explained as follows.He then by means of a simple proportion deduced that log (I 00000 00000 00000 I)=o 00000 00000 00000 0 434 2 944 81 90325 1804, so that, a quantity 1.00000 00000 00000 x (where x consists of not more than seventeen figures) having been obtained by repeated extraction of the square root of a given number, the

**logarithm**of I 00000 00000 00000 x could then be found by multiplying x by 00000 00000 00000 04342 To find the**logarithm**of 2, Briggs raised it to the tenth power, viz.By means of these tables and of a factor table we may very readily obtain the Briggian

**logarithm**of a number to 61 or a less number of places or of its hyperbolic**logarithm**to 48 or a less number of places in the following manner.Suppose the hyperbolic

**logarithm**of the prime number 43,867 required.AdvertisementThe

**logarithm**is then obtained by use of the formula d l d2 l d3 2 log e (x+d) = log e x-f- - x2+3 x3 - &c., in which of course the object is to render dlx as small as possible.An application to the hyperbolic

**logarithm**of is given by Burckhardt in the introduction to his Table des diviseurs for the second million.The best general method of calculating logarithms consists, in its simplest form, in resolving the number whose

**logarithm**is required into factors of the form I - i r n, where n is one of the nine digits, and making use of subsidiary tables of logarithms of factors of this form.All that is required therefore in order to obtain the

**logarithm**of any number is a table of logarithms, to the required number of places, of n, 9n, 99 n, 999 n, &c., for n= I, 2, 3,Taking as an example the calculation of the Briggian

**logarithm**of the number 43,867, whose hyperbolic**logarithm**has been calculated above, we multiply it by 3, giving 131,601, and find by Gray's process that the factors of 1.31601 are (I) 1.316 (5) I.AdvertisementReference should also be made to Hoppe's Tafeln zur dreissigstelligen logarithmischen Rechnung (Leipzig, 1876), which give in a somewhat modified form a table of the hyperbolic

**logarithm**of + Irn.He generalized Weber's law in the form that sensation generally increases in intensity as the stimulus increases by a constant function of the previous stimulus; or increases in an arithmetical progression as the stimulus increases in a geometrical ratio; or increases by addition of the same amount as the stimulus increases by the same multiple; or increases as the

**logarithm**of the stimulus.In the following list, which contains a few typical examples, the different formulae are arranged to give the

**logarithm**of the saturation-pressure p in terms of the absolute temperature 0.A star is said to rise one unit in magnitude when the

**logarithm**of its brightness diminishes by 0.4.If we know n and N, then p is the

**logarithm**of N to base n.AdvertisementAs the table of antilogarithms is formed by successive multiplications, so the

**logarithm**of any given number is in theory found by successive divisions.Thus, to find the

**logarithm**of a number to base 2, the number being greater than i, we first divide repeatedly by 2 until we get a number between I and 2; then divide repeatedly by 10 12 until we get a number between I and 10 y2; then divide repeatedly by ioo v 2; and so on.For a further explanation of logarithms, and for an explanation of the treatment of cases in which an antilogarithm is less than I, see

**Logarithm**.We take out log 2 from the table, halve it, and then find from the table the number of which this is the

**logarithm**.The commonest method of normalization is to take the

**logarithm**of all the values.AdvertisementThe values represent the approximate

**logarithm**of the flux density.The pH scale is the negative

**logarithm**of the hydrogen ion content of water.The axis data must be the common

**logarithm**of frequency in Hertz.The whole-number part of a

**logarithm**is called the characteristic; the fractional part is called the mantissa.To linearise the equation we take the natural

**logarithm**.AdvertisementIf you take the natural

**logarithm**of this distribution, you'll get a normal distribution with mean mu and standard deviation sigma.It follows from these equations that the

**logarithm**of the product of any number of quantities is equal to the sum of the logarithms of the quantities, that the**logarithm**of the quotient of two quantities is equal to the**logarithm**of the numerator diminished by the**logarithm**of the denominator, that the**logarithm**of the rth power of a quantity is equal to r times the**logarithm**of the quantity, and that the**logarithm**of the rth root of a quantity is equal to (r/r)th of the**logarithm**of the quantity.This work contains the first announcement of logarithms to the world, the first table of logarithms and the first use of the name

**logarithm**, which was invented by Napier.For the purpose of thus simplifying the operations of arithmetic, the base is taken to be Io, and use is made of tables of logarithms in which the values of x, the

**logarithm**, corresponding to values of m, the number, are tabulated.For example, suppose the

**logarithm**of 543839 required to twelve places.Advertisement