Search found 3 matches
- Wed Jan 05, 2011 10:51 pm
- Forum: College / University Level
- Topic: Finite number of steps (own)
- Replies: 4
- Views: 7230
Re: Finite number of steps (own)
Nice problem and nice solution. I also think the number of steps needed is 3. Let $f(x)=\dfrac{1}{x}$ and $g(x)=1-x$.So $g\circ f= 1- \dfrac{1}{x},f\circ g=\dfrac{1}{1-x},f\circ g\circ f=g\circ f\circ g=\dfrac{x}{x-1}$. And the fact that the set $\{id,f,g,g\circ f, f\circ g,f\circ g\circ f\}$ is clo...
- Mon Jan 03, 2011 3:09 pm
- Forum: Physics
- Topic: সরল দোলকের বিস্তার
- Replies: 16
- Views: 11845
Re: সরল দোলকের বিস্তার
এইটা দেইখা একটা প্রবলেমের কথা মনে পড়ল| এই ছবিতে সরল দোলকের অবস্থান $a$থেকে$e$যাওয়ার সময় কোনটা ত্বরণকে সঠিকভাবে নির্দেশ করছে?
- Mon Jan 03, 2011 11:30 am
- Forum: Combinatorics
- Topic: Combinatorics Marathon!!
- Replies: 13
- Views: 9332
Re: Combinatorics Marathon!!
This is my first post to this forum :D Let the chosen dates be $ x_{1}<x_{2}<x_{3}<x_{4}<x_{5}$. As there is no consecutive dates, after using the bijection $\{ x_{1},x_{2},x_{3},x_{4},x_{5}\}\leftrightarrow\{ x_{1},x_{2}-1,x_{3}-2,x_{4}-3,x_{5}-4\}$, we find the answer is $\dbinom{31-4}{5}=\dbinom{...