# Dn Sentence Examples

**Dn**, dorsal nerve.- Hence the total flux through the surface considered is - {(dV i /
**dn**l)-}-(dV 2 /**dn**2)}dS, and this by a previous theorem must be equal to 47radS, or the total included electric quantity. - The electric force outward from that point is - dV/
**dn**, where do is a distance measured along the outwardly drawn normal, and the force within the surface is zero. - Hence we have - dV /
**dn**= 4lra or a = - (1 /47r) dV /**dn**= E/42r. - (22) where dV/
**dn**means differentiation along the normal, and v stands d 2 d 2 d2 for the operator a x2 - P dy2 -{- D. - Then bearing in mind that a= (I/4x1-)dV/
**dn**, and p =-(1/4xr)VV, we have finally E 2 c/v=2 f f v.-dS+ 2J J J Vp dv. **Dn**d?- The change of frequency (
**dn**) for a series of lines which behave similarly is approximately proportional to the frequency (n) so that we can take the fraction do/n as a measure of the shift. - Proportional to the rate of variation - dc/dx of the concentration c with the distance x, so that the number of gramme-molecules of solute which, in a time dt, cross an area A of a long cylinder of constant cross section is
**dN**= - DA(dc/dx)dt, where D is a constant known as the diffusion constant or the diffusivity. - "the gas" value the equation becomes -
**dN**= - 7 Adxdt, where R is the usual gas constant, T the absolute temperature, and F the force required to drive one gramme-molecule of the solute through the solution with unit velocity. - If the refractive index for one colour be n, and for another and the powers, or reciprocals of the focal lengths, be 4) and 4)+4, then (I) dï¿½/ 4) =
**dn**/ (n - I) =1 /v; do is called the dispersion, and v the dispersive power of the glass. - Then the following relations hold: 0 = 4)1+4)2= ('nl - I)(I /r' 1 - I /r "1) + (n21)(I/r' 2 - I/r" 2) = (nl- 1) kl+(n2 - i)k 2; and (3) (14) = k l
**dn**l k 2**dn**2. - For example, the condition for achromatism (4) for two thin lenses in contact is fulfilled in only one part of the spectrum, since do /
**dn**1 varies within the spectrum. - A determinant is symmetrical when every two elements symmetrically situated in regard to the dexter diagonal are equal to each other; if they are equal and opposite (that is, if the sum of the two elements be = o), this relation not extending to the diagonal elements themselves, which remain arbitrary, then the determinant is skew; but if the relation does extend to the diagonal terms (that is, if these are each = o), then the determinant is skew symmetrical; thus the determinants a, h, g a, v, - µ 0, v, - h, b, f - v, h, - v, 0, g,f,c c 12, - X, o are respectively symmetrical, skew and skew symmetrical: =0; a,b,c,d a' b' c' d'a" b c d" a, b, c, d a' b' c' d'a", b N' c N'
**dN**,, , c d The theory admits of very extensive algebraic developments, and applications in algebraical geometry and other parts of mathematics.