Trig problem

Given the equation: 1/cotx, for what values of x will the equation be undefined. I am not sure is 180 degrees is an option, because if you substitute it into 1/(1/tanx), the denominator becomes undefined. Does this render the whole equation undefined or =0?

1/1/tanx is just tanx

you need to find for which angles tanx is undefined.
tan x is sinx/cosx which is undefined whenever cosx = 0

which I beleive is n*180 + 90
or 90 ... 270 ... 450 ... etc.

see the attached graph of sine in radians.