Предмет: Математика, автор: Dimo444ka

сколько будет корень из 18?

Ответы

Автор ответа: username2018

$\sqrt{18} = \sqrt{9 \times 2}$
Из девяти можно извлечь корень, поэтому
$\sqrt{9 \times 2} = 3 \times \sqrt{2} = 3 \sqrt{2}$

Dimo444ka: спасибо

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Early file systems were always sequential, meaning that thesuccessive records had to be processed in the order in which they were stored, starting from the beginning and proceeding down to the end. This file structure was appropriate and was in fact the only one possible when files were stored solely on large reels of magnetic tape and skipping around to accessrandom datawas notfeasible.Sequential files are generally stored in some sorted order (e.g., alphabetic) for printing of reports (e.g. a telephone directory) and for efficient processing ofbatches of transactions.Banking transactions (deposits and withdrawals), for instance, might be sorted in the same order as the accounts file, so that as each transaction is read the system needs only scan ahead (never backward) to find the accounts record to which it applies.

When so-called direct-access storage devices (DASD), primarily magnetic disks) were developed, it became possible to access a random data block on the disk. (A data block is the unit of transfer between main memory and auxiliary storage and usually consists of several records.) Files can then be indexed so that an arbitrary record can be located and fetched (loaded into the main memory).

An index of a file is much like an index of a book; it consists of a listing of identifiers that distinguish the records (e.g. names might be used to identify personnel records), along with the records' locations. Since indexes might be long, they are usually structured in some hierarchical fashion and are navigated by using pointers, which are identifiers that contain the address (location in memory) of some item. The top level of an index, for example, might contain locations of (point to) indexes to items beginning with the letters A, B, etc. The A index itself may contain not locations of data items but pointers to indexes of items beginning with the letters Ab, Ac, and so on. Reaching the final pointer to the desired record by traversing such a treelike structure is quite rapid.

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