Question

cot(tan-1 8/5)

Answer 1

u should know this
\[ \large \cot x=\frac{1}{\tan x} \]
and
\[ \large \tan(\arctan x)=x \]

Answer 2

You can also draw a triangle to help in questions like this (though it's not needed here because of the 1/tan(arctan...)

Answer 3

Thanks.