379. Give examples of a function which, as $x$ increases beyond all bounds, a) also increases beyond all bounds, b) tends to a finite limit $a$ (especially to zero); finally, functions which, as $x$ approaches a certain value $p$, c) increases beyond all bounds, d) tends to a certain limit $a$ (especially to zero).
379. a) $x^{2}$, cot $\frac{1}{x} ;$ b) $a-\frac{1}{x^{2}} ; \log \left(1+\frac{1}{x}\right) ;$ c) $a+\operatorname{tg}(x-p)$; $\log (1+x-p)$.