Question

What is tan(arctan 10)?

Answer 1

`tan` and `arctan` are two opposite operations. They cancel each other out. Your answer is `10`.

Your formula in words would be:

"Take the tangent of an angle.
This angle has a size that 'belongs' to a tangent of 10"

`arctan 10=84.289^0 and tan 84.289^0=10`
(but you don't have to do all this)

It's a bit like first multiplying by 5 and then dividing by 5.
Or taking the square root of a number and then squaring the result.