# How do you find the derivative of the function: #arccos ([2x + 1]/2)#?

##### 1 Answer

Apr 17, 2017

# d/dx arccos ([2x + 1]/2) = -1/sqrt(1-(x+1/2)^2)#

#### Explanation:

We want the derivative of:

# arccos ([2x + 1]/2) = arccos (x+1/2)#

We can use the known result:

#d/dx arccos x = -1/sqrt(1-x^2)#

Along with the chain rule to get:

# d/dx arccos ([2x + 1]/2) = -1/sqrt(1-(x+1/2)^2) * d/dx (x+1/2)#

# " " = -1/sqrt(1-(x+1/2)^2)#