@shinee

Then your video cam does not have high enough frame rates.

If you have seen on discovery and national geographic they use high speed cameras (with fram rates > 1000 frames per second!) to observe bullets being shot from a gun.

@ naughtygal

coprime means that the GCD of p& q is 1. eg. 3 and 4 are coprime. 19 and 102 are coprime

@ ankurgupta91

how is it continuous at irrational.

@hsbhatt sir

"So, from this, if you consider a sequence of rational numbers that in the limit is an irrational number, the limit of the sequence is definitely non-zero"

Sir how can you say it will be non zero.

"The numerator  of the bracketed expression is an odd number and the denominator is 2ⁿ.



So, again, we see that the denominator does not tend to q for the members of the sequence."

Sir please could you explain this part I did not understand it.

@sachinguptaiit 

but q is not constant it mqaybe q is very large so 1/q ----------> 0

I'm not saying its right or wrong unless you post the explanation

No that is not correct.

I also thought that that this is the answer (this came in a test given by my teacher).

let f be a function defined in (0,1) given by

f(x) = 0 if x is irrational

and f(x) = 1/q if x is a rational of the form p/q (p,q are positive integers and are coprime)

(a)  f(x) is continuous at rational points in (0,1)

(b)  f(x) is discontinuous at rational points in (0,1)

(c)  f(x) is continuous at irrational points in (0,1)

(d)  f(x) is discontinuous at irrational points in (0,1)

Note: More than 1 option maybe correct.

Please give an explanation of your answer.

Oh no I got 9 as the minimum. So either the answer is 9 or less than that (very unlikely)

edited

I don't know if you are right in your approach. I tried solving along those linesbut could not get anything out of it.

I am posting this because I don't know the solution

Please somebody solve question no. 3 and no. 4 in this post:

http://www.goiit.com/posts/list/games-puzzles-and-quizzes-maths-puzzles-66751.htm

I like Internet Explorer 7 with IE7pro addon,. Try it its great

I have tried proving it using induction.

Please correct if wrong

Hey this is a forum for discussing questions. There don't have to be any personal attacks on Goiit.

I think the admin should intervene and take appropriate action

@ rudra your post

3 Jul 2008 12:41:03 IST     Subject: A.P

What if we consider the lowest rung is at 25 cm above the ground level? The last rung is at 250 cm (from the lowest rung). So 25+(n-1)25=250 then n=10..??????

If the lowest rung is at 25 cm level then the topmost will be 250cm above the bottom most rung i.e. at 275cm

@ vasanth

Your explanaion is clear to me.

Let me try putting it in another way: 

In the question it says ' from 45cm at the bottom ' which can mean that the lowest rung of the ladder may or may not be at the ground level.

Lets  say x cm above ground there is a rung which is the bottom rung. Then the topmost rung is x + 2.5 metres above the ground.

so x + (n-1) 25 = x + 250

so n = 11

I hope now your doubts are clear.