Home
Class 12
MATHS
If (1+x)^(15)+C(0)+C(1)x+C(2)x^(2)+C(3)x...

If `(1+x)^(15)+C_(0)+C_(1)x+C_(2)x^(2)+C_(3)x^(3)+ . . .+C_(15)x^(15) and (k=C_(2)+2C_(3)+3C_(4)+ . . .+14C_(15))` then the value of `(k-993)/(1000)` is equal to______

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to find the value of \( k \) defined as: \[ k = C_2 + 2C_3 + 3C_4 + \ldots + 14C_{15} \] where \( C_n \) represents the binomial coefficients from the expansion of \( (1+x)^{15} \). ### Step 1: Understanding the Binomial Expansion The binomial expansion of \( (1+x)^{15} \) is given by: \[ (1+x)^{15} = C_0 + C_1 x + C_2 x^2 + C_3 x^3 + \ldots + C_{15} x^{15} \] ### Step 2: Finding the Value of \( k \) To find \( k \), we can use the property of binomial coefficients. We can express \( k \) in terms of derivatives of \( (1+x)^{15} \): \[ k = \sum_{n=2}^{15} (n-1) C_n = \sum_{n=2}^{15} n C_n - \sum_{n=2}^{15} C_n \] The first sum can be computed using the derivative of \( (1+x)^{15} \): \[ \frac{d}{dx} (1+x)^{15} = 15(1+x)^{14} \] Evaluating this at \( x=1 \): \[ 15(1+1)^{14} = 15 \cdot 2^{14} \] ### Step 3: Evaluating the Second Sum The second sum \( \sum_{n=0}^{15} C_n \) is simply \( (1+1)^{15} = 2^{15} \). Thus, we have: \[ k = 15 \cdot 2^{14} - 2^{15} \] ### Step 4: Simplifying \( k \) We can simplify \( k \): \[ k = 15 \cdot 2^{14} - 2 \cdot 2^{14} = (15-2) \cdot 2^{14} = 13 \cdot 2^{14} \] ### Step 5: Calculating \( 2^{14} \) Calculating \( 2^{14} \): \[ 2^{14} = 16384 \] Thus, \[ k = 13 \cdot 16384 = 212992 \] ### Step 6: Finding \( \frac{k - 993}{1000} \) Now we need to calculate: \[ \frac{k - 993}{1000} = \frac{212992 - 993}{1000} = \frac{211999}{1000} = 211.999 \] Since we are looking for an integer value, we take the floor value: \[ \frac{211999}{1000} = 211 \] ### Final Answer The final value is: \[ \boxed{211} \]
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • BINOMIAL THEOREM

    AAKASH INSTITUTE ENGLISH|Exercise Assignment (section-J) Objective type question (Aakash Challengers Questions)|4 Videos
  • BINOMIAL THEOREM

    AAKASH INSTITUTE ENGLISH|Exercise Assignment (section-H) Objective type question (Multiple True-False Type Questions)|2 Videos
  • APPLICATION OF INTEGRALS

    AAKASH INSTITUTE ENGLISH|Exercise Assignment Section - I Aakash Challengers Questions|2 Videos
  • COMPLEX NUMBERS AND QUADRATIC EQUATIONS

    AAKASH INSTITUTE ENGLISH|Exercise section-J (Aakash Challengers Qestions)|13 Videos

Similar Questions

Explore conceptually related problems

If (1+ x)^(n) = C_(0) + C_(1) x + C_(2)x^(2) + ...+ C_(n)x^(n) , prove that C_(1) + 2C_(2) + 3C_(3) + ...+ n""C_(n) = n*2^(n-1)

If (1 + x)^(n) = C_(0) + C_(1)x + C_(2) x^(2) + …+ C_(n) x^(n) , then for n odd, C_(1)^(2) + C_(3)^(2) + C_(5)^(2) +....+ C_(n)^(2) is equal to

(1 + x)^(n) = C_(0) + C_(1) x + C_(2) x^(2) + C_(3) x^(3) + … + C_(n) x^(n) , prove that C_(0) - 2C_(1) + 3C_(2) - 4C_(3) + … + (-1)^(n) (n+1) C_(n) = 0

If (1 + x)^(n) = C_(0) + C_(1)x + C_(2) x^(2) + C_(3) x^(3) + …+ C_(n) x^(n) prove that (C_(0))/(1) + (C_(2))/(3) + (C_(4))/(5) + ...= (2^(n))/(n+1) .

(1+x)^(n)=C_(0)+C_(1)x+C_(2)x^(2)+….+C_(n)x^(n) then C_(0)C_(2)+C_(1)C_(3)+C_(2)C_(4)+…..+C_(n-2)C_(n) is equal to :

Evaluate : 1+^(15)C_(1)+^(15)C_(2)+^(15)C_(3)+......+^(15)C_(15)

Evaluate : 1+^(15)C_(1)+^(15)C_(2)+^(15)C_(3)+......+^(15)C_(15)

Let n be a positive integer and (1+x)^(n)+C_(0)+C_(1)x+C_(2)x^(2)+C_(3)x^(3)+ . . .+C_(r)x^(r)+ . . .+C_(n-1)x^(n-1)+C_(n)x^(n) Where C_(r) stands for .^(n)C_(r) , then Q. The value of underset(r=0)overset(n)(sum)underset(s=0)overset(n)(sum),C_(r),C_(S) is

Let n be a positive integer and (1+x)^(n)+C_(0)+C_(1)x+C_(2)x^(2)+C_(3)x^(3)+ . . .+C_(r)x^(r)+ . . .+C_(n-1)x^(n-1)+C_(n)x^(n) Where C_(r) stands for .^(n)C_(r) , then Q. The values of underset(r=0)overset(n)(sum)underset(s=0)overset(n)(sum)(C_(r)+C_(S)) is

If (1+x)^(n)=C_(0)+C_(1).x+C_(2).x^(2)+C_(3).x^(3)+......+C_(n).x^(n), then prove that C_(0)+2C_(1)+4C_(2)+6C_(3)+...+2n.C_(n)=1+n*2^(n)