Tangent function
= Tangent function
{title2=$\tan x=\sin x/\cos x$}
A <trigonometric function> defined where $\cos x\ne0$. It has real <simple poles> at $(n+1/2)\pi$, and $\tan((n+1/2)\pi+\delta)=-\cot\delta$. This local pole identity generates the <large roots near tangent poles>.