Methods for fast multiplication

Published May 01, 2018 In everyday life, we do not rarely have to multiply the numbers. Sometimes it needs to be done quickly, like calculators-virtuosos. The methods of fast multiplication are used for cross multiplication, which is very useful when operating with two-digit numbers. This way used in the olden times by the Greeks and Hindus and was called by the way of rapid multiplication by a cross...

Small numbers

Published May 01, 2018 Small numbers in mathematics are no less interesting than numerical giants. These are numbers that are as many times less than one, as much as one less than a numerical giant. Small numbers can be obtained by writing a series of numbers that are inverse to a million, a billion, a billion, etc., that is, divide the unit by these numbers. The resulting fractions...

How to find the angle of the known sine

Published May 01, 2018 In everyday life, to solve trigonometric problems, one must know how to find the angle over a known sine. It turns out that this is not difficult at all. To do this, remember that sin150 = 0.26, sin300 = 0,5, sin450 = 0,707 and sin900 = 1, which are known to everyone from school geometry. In addition, for intervals from 150 to 300 and from 300 to 450 it is necessary to know that sinuses can be calculated as follows...

The protractor "by one's own hands"

Published May 01, 2018 In some cases, for example, during a country walk, you have to roughly measure the angles. But even the simplest homemade goniometer is not always under the arm. In such cases, our own fingers will help - the protractor "with our own hands", which is always with us. Of course, the measurements will be rough approximations, but still, more reliable than the estimation just by eye...

Muscle strength

Published May 01, 2018 Observing the work of an ant, sometimes you ask yourself a puzzling task: where does this insect take such a muscle strength, so that it is ten times heavier than the body to drag the load without apparent tension? This is equivalent to a person running on a ladder, holding on his shoulders, for example, a piano - and, after all, the ratio of cargo to body weight of an ant is about the same. It turns out that the ant is relatively stronger than man?..

The angle of the eye

Published May 01, 2018 The angle of the eye is the angular space seen by the eye with a fixed view and a fixed head. The average person has a field of view: 550 up, 600 down, 900 outward and 600 - inside. This is true only for achromatic vision (this is due to the fact that on the edges of the retina there are no receptors of cones that can distinguish color)...

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