1/x=1/tan^(-1)t
Note that 1/x=x^(-1) does not mean that 1/x=tant
as x=tan^(-1)t means the angle x, whose tangent is t and this does not mean that tangent of angle 1/x is 1/t or 1/tant or any other thing apparently similar.
In short, tan^(-1)t is different from 1/tant. The fact is that the latter is cott, a ratio, while x is an angle, which could be in degrees, radians or even Grads.