I have this question

Express tan (90 + x) in terms of tan x

not really sure what to do with it, using the compound angles i have gotten this far

$\displaystyle \frac{tan90+tanx}{1-tan90tanx}$

= $\displaystyle \frac{\infty+tanx}{1-\infty tanx}$

not really sure how to proceed from there, or if that is an acceptable answer, or i am going about this in completely the wrong way

thanks