I heard something twittering on the balcony. Walking on my tiptoe, I reached the window, through which I spotted a turtle dove standing on the stainless-steel-made railing, with a sprig in its beak. B

The bell is about to ring. The new year is in sight. Time flies as we grow and mature, leaving naivety behind. No sooner have we relived the past year in detail than we face the coming year hurriedly.

He could feel drizzle patting his face. To the best of his ability, he stood up. Anew, darkness enveloped him. He pondered about what he had just experienced, which was patently a dreadful nightmare.

He had no idea where he was. And a strong feeling that he had never experienced before occupied his mind little by little. The light was still there. So dim and nebulous was it that the dread of being

He was born blind. He had suffered the darkness for years which he had been accustomed to, till that day, when something mysterious happened. Abruptly he felt a soft, faint beam pierced the darkness,

One-dimensional motion$$\begin{align}v_f&=v_i+a \Delta t \\\Delta x&=v_i \Delta t+{a \Delta t^2 \over 2} \\\Delta x&={v_i+v_f \over 2} \Delta t \\v_f^2&=v_i^2+2a \D

题目描述$n$ black and white balls were put into a bag. Petya doesn’t know exactly how many black balls are there among them. He knows, however, that there are $0, 1, \ldots, n$ black balls among all balls

题目描述Given a positive integer $n$ and a positive prime number $p$, find $x, y$ and $z$ such that $x^n+y^n \equiv z^n \pmod p$ and $x, y$ and $z$ are nonzero modulo $p$ or report that there’s no such tr

题目描述Consider $n$ distinct points on a plane. Two points from that set are said to be friends, when there exists a rectangle with sides parallel to coordinate axes that contains those two points and do

题目描述Traveller Gregory is famous for his ability to always choose the shortest path for his journey. Ostap is a journalist who seeks for information about the recent Gregory’s trip. He managed to get t