Question

How do you evaluate `tan^-1(tan((3pi)/10))`?

Answer 1

`3pi/10`

Answer 2

`(3pi)/10`

Explanation:

`tan^-1x" and" tanx" are " color(blue)"inverse functions"`

and in general

`color(orange)"Reminder " color(red)(|bar(ul(color(white)(a/a)color(black)(f^-1(f(x))=x)color(white)(a/a)|))`

`rArrtan^-1(tan((3pi)/10))=(3pi)/10`