Determination of values of the simplest trigonometrical functions sometimes nonpluses. It is possible to count a cotangent in several ways, having used the calculator or, knowing value of other trigonometrical functions.
Instruction
1. The cotangent of an acute angle is defined as a ratio of an adjacent leg to opposite, other name - an addition tangent. Values of standard corners are studied within a school course of geometry. The cotangent of corners 30 ° and 60 ° makes √3 and 1 / √ 3 respectively. Since division into zero is inadmissible operation in mathematics, the ctg 0 value is absent, ctg 45 makes 1, in this case the rectangular triangle is isosceles, and the cotangent of a corner 90 ° is equal to zero.
2. Knowing value of a cosine and sine of the angle, it is possible to define its cotangent: divide a cosine into a sine, and you receive what was looked for. Besides, if you know value of a tangent, count a cotangent on a formula: ctg x = 1/tg x where a X-corner, ctg is a cotangent, tg is a tangent. To define a sine and a cosine of the angle, use the main trigonometrical identity: sin x+cos x=1.
3. For calculation of a cotangent it is possible to use special tables which are called Bradis's tables. They serve for determination of value of trigonometrical functions. It is possible to see them in mathematical reference books, or to find without effort on thematic resources in the Internet. There are various options: the simplified tables and expanded by which it is possible to define cotangents of non-standard corners.
4. For definition of a cotangent use the built-in calculator of the Windows operating system. To include a possibility of calculation of trigonometrical functions select a menu item "Look", in the falling Engineering list. Enter value of number which cotangent you want to calculate, press the button with the inscription tg, then on the button with the inscription "1/x" — where x — value of a tangent. Except the built-in calculator, it is possible to define values of the main trigonometrical functions, having used various online calculators.