# What does #cos(arctan((3pi)/4)) # equal?

##### 1 Answer

Mar 11, 2018

#### Explanation:

This is a rather curious question, since

Nevertheless

Consider a right angled triangle with angle

Then:

#tan theta = "opposite"/"adjacent" = (3pi)/4#

#cos theta = "adjacent"/"hypotenuse" = 4/sqrt(9pi^2+16)#

Then:

#cos(arctan((3pi)/4)) = cos theta = 4/sqrt(9pi^2+16)#