MATHEMATICS DBT 2

PROB 1
PROB 2
PROB 3
PROB 4
PROB 5

30 Answers

11
rkrish ·

Prob 1

Ans : B ?????????????

62
Lokesh Verma ·

power play among all the options given see carefully only 37 is of the form 4n+1

1
playpower94 ·

thanks @bhaiya [1] ... but answer is 37 ...

62
Lokesh Verma ·

x_{n+1}=\frac{1+x_n}{1-x_n}

x_{n+2}=\frac{1+x_{n+1}}{1-x_{n+1}}

x_{n+2}=\frac{1+\frac{1+x_{n}}{1-x_{n}}}{1-\frac{1+x_{n}}{1-x_{n}}}

x_{n+2}=\frac{2}{-x_{n}}

x_{n+4}=\frac{2}{-x_{n+2}}

x_{n+4}=\frac{2}{-\frac{2}{-x_{n}}}
x_{n+4}=x_{n}

thus k=4n+1 for all n

62
Lokesh Verma ·

ok trying.. :)

1
playpower94 ·

bhaiya one of the unsolved is wat rkrish
2 has edited .. pls help wid dat

1
playpower94 ·

bhaiya one of the unsolved is wat rkrish
2 has edited .. pls help wid dat

62
Lokesh Verma ·

playpower dude.. i have asked this more than once..
can you please post the questions that are unsolved with a better image or in text...

I guess i have real readability issues..
also if you could tell me exactly which questions to solve!

1
playpower94 ·

someone please help HELP!!!!!! the SUMS

1
playpower94 ·

well its xn+1 not xn+k

11
rkrish ·

Is this the question ????

Prob 3

x_{n+1} = \frac{1+x^{n}}{1-x^{n}} for all n \epsilon N and x_{k}=x_{1}=35

Find k.

1
playpower94 ·

[5] wat a method , tukka style [3]

11
rkrish ·


See at ur own risk !!


Put n=4

Total no. of ways = 4! = 24

a) 6(16-27+2) < 0 XXX

b) 12(9-8+1) = 24 √

c) 24(3-1) - 24(4-4) = 48 X

11
rkrish ·

I solved it by some shortcut which I don't know is useful and correct always or not.

1
playpower94 ·

YEAH TRUE PLEASE SHOW THE METHOD

11
Anirudh Narayanan ·

Playpower, in prob 1: does each urn contain n balls of each color or is total number of balls is n?

1
Optimus Prime ·

WHERE BELOW?

1
playpower94 ·

SOMEONE PLEASE HELP ABOUT PROBLEM NO. 1 .. THE SUM IS REWRITTEN ABOVE for the 2nd time .. FOR CLEAR VIEW

1
kamalendu ghosh ·

1
playpower94 ·

please post the solution of sum no. 1

13
Двҥїяuρ now in medical c ·

is the ans B??

for the first one?

1
playpower94 ·

PROBLEM 1
n balls are picked one by one from 4 urns each containing n identical balls of green , red , white and blue colours . The number of ways , when no 2 consecutive pickings are from the same urn and balls of all the colours are picked , are
a> 6(4^{n-2}-3^{n-1}+ 2^{n-3})
b>12(3^{n-2}-2^{n-1}+ 1)
c>24(3^{n-3}-2^{n-4})-24(n-4)
d> none of these

11
rkrish ·

Can u pls latexify the other questions.They're not clearly visible.

1
playpower94 ·

YUP THNKS i got i [1]
@ rkrish
pls try other sums

11
rkrish ·

I hope you got this :
N = 24 . 54 . ......

After this ,

you have to get

(p1+1)(p2+1)(p3+1)....(pn+1) = 105

105 = 3.5.7 = (2+1).(4+1).(6+1) √
= 15.7 = (14+1).(6+1) √
= 5.21 = (4+1).(20+1) √
= 3.35 = (2+1).(34+1) X (this is not possible as we know that N = 24 . 54 . ......... )

So, at the most 3 prime factors are possible (2,5 & a)
Hence, the cases mentioned above.

1357
Manish Shankar ·

Yes rkrish

good work

11
rkrish ·

am i rite Manish bhaiyya ??????

11
rkrish ·


Prob 4

N = a1p1 . a2p2 . a3p3 . .... . anpn

(p1+1)(p2+1)(p3+1)....(pn+1) = 105 (which is odd)

So, p1,p2,p3, ... ,pn should all be even.

\Rightarrow N should be a perfect square.

N = 23 . 53 . ...........

So, definitely N is also divisible by 10000 (since powers of prime factors are even).

N = 24 . 54 . ...........

Now, 105 = 3 . 5 . 7

So, power of 2 & 5 cannot be 4 simultaneously.

So,
either N = 24 . 56 . a2
or N = 26 . 54 . a2
or N = 24 . 520
or N = 220 . 54
or N = 26 . 514
or N = 214 . 56

Therefore,
Total no. of odd factors can be = 12 , 8 , 20 , 4 , 14 or 6

Hence options A,B,C,D are correct.

1
playpower94 ·

someone please help the sums

11
Anirudh Narayanan ·

no wat i am asking is, is there n balls of each color or n balls in each urn irrespective of the number of balls of each colour?

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