Remember some of the values of the inverse cosine, if you have to return from time to time to its calculation: arc cosine of -1 is equal to PI (in radians), which corresponds to 180°; arc cosine of -1/2 equal to 2/3 of PI or 120°;- the arc cosine of 0 is equal to half of PI, or 90°; arc cosine of 1/2 is equal to 1/3 PI or 60°;- the arc cosine of 1 is equal to zero, both in radians and in degrees;
Use built-in calculators search engines Google or Nigma, if you need to obtain the calculation result of the inverse cosine in radians. To do this, simply enter a search term - for example, to calculate this function from the number of 0.58, type in the search box "the arc cosine 0.58" or "arccos 0.58".
Calculate the value of the arc cosine using the software calculator Windows, if you need the result in degrees. This feature can be accessed through the main menu system on the button "start" - search for the link "Calculator" in the section "Service", which is placed in the subsection "Standard" under "All programs."
Use a scientific or engineering version of the calculator interface, as in open by default, standard version of trigonometric functions. Open the "View" menu and choose the corresponding line.
Enter a numeric value, the inverse cosine which you want to search, and then tick the checkbox labeled Inv. This mark inverts the trigonometric functions, placed on the control buttons of the calculator. So when you click the button labeled cos, the calculator will apply to the specified number a function of the inverse cosine.
The result by default, you will get degrees, but if necessary, you can specify other measurement units (radians and grads), by ticking the appropriate field of the calculator interface.