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Catalogs Discussion Forums -> About IITs and JEE -> strm in IIT -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
4 replies   
jadavpur would be better .since it is in consideration for iit status,a good stream there would definitely do good
Catalogs Discussion Forums -> Mechanics -> ROTATIONAL MECHANICS -> Go to message
This Post 2 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
2 replies   
sorry i don't have the diagram.
 
let r be the radius of sphere
the friction would  rotate the sphere
before collision angular momentum due to centre of mass and the friction would oppose each other
 
before collision = Mvr - Iw = Mvr - ( 2/5)Mvr = (3/5)Mvr
let velocity after collision be u
conserving the angular momentum before and after collision
(3/5)Mvr = ( 2/5)Mur + Mur
 
u = 3v/7
Catalogs Discussion Forums -> Differential Calculus -> for puneet -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
10 replies   
Thanks Vinu .i have realised my mistake
Catalogs Discussion Forums -> Differential Calculus -> for puneet -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
10 replies   
Mr . rony kindly edit your post
Catalogs Discussion Forums -> Differential Calculus -> for puneet -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
10 replies   
 lim {1-(m/n)}^n = e^(-m)
 n->i
 
i means infinity
 
 lim  n!/((n-x)!*x!) (m/n)^x*{1-(m/n)}^(n-x)
 n->i
 lim  n!/((n-x)!*x!)* [(m/n)^x*{1-(m/n)}^n )/(1 - ( m/n))^x
 n->i
 
 usind
 lim {1-(m/n)}^n = e^(-m)
 n->i
 when  n->i  { [n!/(n-x)!]/n^x} becomes  1
 
 therefore we get {e^(-m)*m^x}/x!

 
Catalogs Discussion Forums -> Vectors -> question on vectors -> Go to message
This Post 2 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
2 replies   
if a line makes angle a , b ,c with x ,y ,z axis then

(cosa)^2 + (cos b)^2 +(cos c)^2 =1

given cos a =cos b= cos c

therefore cos a = +- [1/ sqrt(3)]

components of vector A

A * ( cos a I + cos b J +cos c K )

I ,J ,K are unit vectors
Catalogs Discussion Forums -> Algebra -> no of equations -> Go to message
This Post 2 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
6 replies   
p = [ (x^3) +2]/x
 
for maximum value of p dp/dx = 0
 3 (x^3)  - (x^3) -2 =0
 
which gives x= 1
therefore maximum value of p= 3
 
f(x) = x^3 -px +2
 
for real roots p should be greater than 0
 
number of values of p 1,2,3
 
hence number of equations is 3
 
Catalogs Discussion Forums -> Organic Chemistry -> plzz tell me -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
4 replies   
treat
1-nitro propane is,
CH 3-CH2 -CH2 -NO2
and,
2-nitro propane is,
CH3 -CH-CH3
        I
        NO2
 
 
 
 
 
 
with Sn /HCL A WHICH WILL CONVERT IT TO AMINES . THEN WE HAVE TO TREAT WITH DILUTE NITROUS ACID WHICH CONVERT NH2 GROUP TO DIAZONIUM SALT  WHICH WHEN TREATED WITH WATER WILL FORM OH GROUP. THEN WE PERFORM VICTOR MEYER'S TEST TO DIFFERENTIATE 1 DEGREE AND 2 DEGREE ALCOHOL


Catalogs Discussion Forums -> Organic Chemistry -> organic chemistry -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
7 replies   
 hi   AJAYAVSS
 
considering that the disc is removed from the right end
 
 the centre of mass of the complete disc is at the centre of disc
 
 { if the disc is removed from the right end the centre of mass of the   remaining portion would move towards the left  of origin }
 
  Let the centre of mass  of the  remaining portion  move towards the left  of origin  by a distance 'x '
 
distance between the centre of removed portion and centre of disc
  = 2R -R = R
 
let the mass per unit area be  'a '
mass of remaining portion = (pie)*a*[ (2R)^2 - R^2]
                          = (pie)*a*3(R^2)
 
mass of removed portion= (pie)*a*(R^2)
 
Taking moments about the origin between the remaining part and removed part

      (pie)*a*3(R^2) * x = (pie)*a*(R^2) * R
            
               x  = R /3
 
the centre of mass of remaining portion moves towards the left  of origin  by a distance R/3
 
[ if the disc is removed from the left end the centre of mass of the   remaining portion would move towards the right of origin ,but the distance would remain same ]
 
Catalogs Discussion Forums -> Algebra -> A PROBABILITY ON G.P -> Go to message
This Post 10 points    (Olaaa!! Perrrfect answer.   in 2 votes )   [?]
5 replies   
 numbers  in G.P can be taken as a , ar ,a(r^2),where a is the 1st term and r is the common ratio
 
there are 100 numbers
 

CASE 1:
let us start by taking the r =2 ,therefore r^2 = 4    
possible numbers from which choice of a can be made= 100/4 = 25
 
CASE 2:
let  the next value of r =3 ,therefore r^2 = 9    
possible numbers from which choice of a can  be made=100/9 =11
  { we take only the maximum number divisible i.e the quotients}
 

CASE 3:
let  the next value of r =4 ,therefore r^2 = 16   
possible numbers from which choice of a can  be made=100/16 =6
 
CASE 4:
let  the next value of r =5 ,therefore r^2 = 25   
possible numbers from which choice of a can  be made=100/25 =4

CASE 5:
let  the next value of r =6 AND r=7,therefore r^2 = 36 and 49 respectively   
possible numbers from which choice of a can  be made=100/36 +100/49= 4
 { takin only the quotient of the division}
 
 
CASE 6 :
 
when r=8, 9,10 the maximum numbers divisible is 1 each .since r^2=(64,81,100)
so total number is 1+1+1=3
 
 
 
 
WE DO NOT TAKE ANY FURTHER VALUES OF r SINCE IT WOULD EXIT THE LIMIT 0F 100
 
 
n(E) = event that the numbers in GP is the sum of the abve cases
       = 25 + 11 +6 +4 +4+ 3 =53  
 
n(S)= sample space of choosing 3 numbers is 100C3

probability = n(E)/n(S)
 
            = 53/ 100C3
            = 53/161700
Catalogs Discussion Forums -> Optics -> optics -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
6 replies   
refractive index (n) = apparent depth/real depth

if displacement with respect to unit time is taken = (9/n)

actual velocity= (9/n) - 3

n is the refractive index of water
Catalogs Discussion Forums -> Integral Calculus -> integral calculus gamma function -> Go to message
This Post 2 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
2 replies   
[ 0][pi/2]sinmx.cosnx.dx  = {G [( m+1)/2] *G [(n+1)/2] } / 2*G[ ( m+n+2)/2]
 
 
 
denoting
 beta function by B ALSO KNOWN AS 1ST EULERIAN INTEGRAL
gamma function by G ALSO KNOWN AS 2ND EULERIAN INTEGRAL
 
 B(n,m)= INTEGRATION OF  x^(n-1)*[(1-x)^(m-1)] WITH LIMITS FROM 0 TO 1
 G(k)= INTEGRATION OF  e^(-x)*[(x)^(k-1)] WITH LIMITS FROM 0 TO INFINITY
  WHERE n,m,k are all REAL NO.S greater than zero
 
 STANDARD RESULTS

1) G(n+1)=nG(n)
  IF n IS A +VE  INTEGER THEN G(n+1)=n!
2) G(1)=1
3) B(m,n)=B(n,m)={G(m)G(n)}/G(m+n)
4) G(m)G(1-m)=(PIE)/SIN(mPIE) WITH (0<m<1)
 USING THIS STANDARD RESULTS MANY CALCULATIONS CAN BE MADE EASY
 
Catalogs Discussion Forums -> Algebra -> Maths doubt!!! -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
16 replies   
considering a number N

N = (p^a)* (q^b)*(r^c)*(s^d)

where p ,q,r,s are odd numbers and a,b,c,d are integers

now for a number N it's divisors are = (1+a)*(1+b)*(1+c)*(1+d)

APPLYING THE METHOD OF CONTINUOS DIVISION

let us start with 1st prime number 2

divide 1000 by 2 , quotient = 500

next prime number is 3 product of 2*3 =6

divide 1000 by 2*3 , quotient = 166

next prime number is 5 product of 2*3*5 =30

divide 1000 by 2*3*5 , quotient = 33

next prime number is 7 product of 2*3*5*7 =210

divide 1000 by 2*3*5*7 , quotient = 4

we cannot further divide as of 2*3*5*7*11 exceeds 1000

we have got the last quotient = 4 and last divisor =210

therefore the largest number divisible is =210*4=840
Catalogs Discussion Forums -> Algebra -> For a genuine genius -> Go to message
This Post 2 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
10 replies   
a = 111111...............81 times
 
a =  (1/9)9999999.............81 tmes
 
a = (10^81 - 1)/ 9
 
a = (10^81 -1)/ (10 -1)
 
a is the sum of  G.P whose  common ratio is 10 consisting of 81 terms
 
hence a is divisible by 9
 
the correct option is a)
 
i may be wrong
Catalogs Discussion Forums -> Algebra -> nature of roots of an eqn -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
16 replies   
hit_ur_hit whatever i have written is directly picked up from

HALL AND KNIGHT ALGEBRA
CHAPTER - THEORY OF EQUATIONS .CONTEXT NUMBER 557
 
 
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