Ethnology – science about nationalities, their customs, cultural and religious features. It was created in the 19th century. Formation of this sphere of historical and humanitarian knowledge is closely connected with other sciences about the person.

Process of finding of derivative function is called differentiation. The same function can at some values of an argument have a derivative, and at others — not to have.

Any collective whatever it was on number of participants and orientation is non-uniform. Relationship between members of the group can be the most various, and not always these features can be available to direct observation. For studying a microclimate in collective various social and psychological methods, one of which is creation of a sotsiogramma – the scheme reflecting relationship in group, are used.

Of course, centimeters and cubes (centimeters cubic) serve for measurement of different physical units. However in practice sometimes it is necessary to use both units of measure. Naturally, at the same time additional information which can be specified, proceeding from specific conditions of a task is necessary.