If necessary to multiply or divide several numbers of a question what tool to use, does not arise. And here what to consider something more difficult (for example, value of the inverse trigonometrical function) - a question with a little less obvious answer. How in practice to count value **of an arctangent**?

## Instruction

1. There are several ways to calculate value of an arctangent. One of them is known to us from school - to use Bradis's tables. Sometimes, in field conditions, this option can be the only thing.

2. Other way is to use the Windows OS standard calculator. For this purpose at first switch it to the expanded mode - in the menu, in the section "Look" select the Engineering item and then action buttons in the calculator considerably will increase.

3. After that enter value from which you need to calculate an arctangent - it can be done also from the keyboard, and clicking the necessary keys on the calculator, both having just copied and having inserted the necessary value (CTRL + C and CTRL + V). Then choose type of units of measure in which you need to receive the answer (in radians, degrees or childbirth) - it becomes the choice of one of three values of the switch under the entry field of the calculated value. Then give a mark in a cell with the inscription ""Inv"" - it inverts trigonometrical operations. Now, having pressed the button with the inscription ""tg"", you receive value of function, the return to a tangent, that is value of an arctangent necessary to you.

4. And, of course, in an age of the Internet in network cannot but exist the resource suggesting to solve and this problem online. Online calculators have the convenient interface and opportunities which were more advanced in comparison with the standard Windows calculator - for example, it is possible to calculate not only value of one function, but also expression from several functions.