# Power Pivot Principles: The A to Z of DAX Functions – ACOT

6 July 2021

*In our long-established Power Pivot Principles articles, we are starting a new series on the A to Z of Data Analysis eXpression (DAX) functions. This week it’s ACOT without a baby…*

*The ACOT function*

This function returns the principal value of the arccotangent (inverse cotangent) of a number (which is not the same as the reciprocal of the cotangent). This needs some explanation. Consider a right-angled triangle:

Using the age-old mathematics mnemonic **SOHCAHTOA**, we get:

**sin x**= opposite / longest side (hypotenuse) = O/H**cos x**= adjacent / hypotenuse = A/H**tan x**= opposite / adjacent = O/A**cotan x**=**1 / tan x**= adjacent / opposite = A/O**arccotan y**=**cotan**is the angle whose cotangent is^{-1}y**y**.

This may be charted as follows:

The syntax is very simple:

**=ACOT(number)**

There is only one argument:

**number:**the cotangent of the angle you want.

Please see my example below:

Again, this is pretty straightforward.

*Come back next week for our next post on Power Pivot in the **Blog** section. In the meantime, please remember we have training in Power Pivot which you can find out more about **here**. If you wish to catch up on past articles in the meantime, you can find all of our Past Power Pivot blogs **here**.*