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If C(0),C(1), C(2),...,C(N) denote the b...

If `C_(0),C_(1), C_(2),...,C_(N)` denote the binomial
coefficients in the expansion of `(1 + x)^(n)` , then
`1^(3). C_(1)-2^(3). C_(3) - 4^(3) . C_(4) + ...+ (-1)^(n-1)n^(3) C_(n)=`

A

0

B

`n^(3) 2^(n)`

C

`n(n-1)(n-2)2^(n-3)`

D

`2^(n)`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to evaluate the expression: \[ S = 1^3 \cdot C_1 - 2^3 \cdot C_3 - 4^3 \cdot C_4 + \ldots + (-1)^{n-1} n^3 \cdot C_n \] where \( C_r \) are the binomial coefficients from the expansion of \( (1 + x)^n \). ### Step-by-Step Solution: 1. **Understanding the Binomial Coefficients**: The binomial coefficients \( C_r \) are given by: \[ C_r = \binom{n}{r} = \frac{n!}{r!(n-r)!} \] for \( r = 0, 1, 2, \ldots, n \). 2. **Rewriting the Expression**: We can rewrite the expression \( S \) as: \[ S = \sum_{r=1}^{n} (-1)^{r-1} r^3 C_r \] 3. **Using the Binomial Theorem**: The binomial theorem states that: \[ (1 + x)^n = \sum_{r=0}^{n} C_r x^r \] We can differentiate this expression to find relationships involving \( r \) and \( C_r \). 4. **Differentiating the Binomial Expansion**: Differentiate \( (1 + x)^n \) three times: \[ \frac{d}{dx}(1 + x)^n = n(1 + x)^{n-1} \] \[ \frac{d^2}{dx^2}(1 + x)^n = n(n-1)(1 + x)^{n-2} \] \[ \frac{d^3}{dx^3}(1 + x)^n = n(n-1)(n-2)(1 + x)^{n-3} \] 5. **Evaluating at \( x = -1 \)**: We substitute \( x = -1 \) into the third derivative: \[ \frac{d^3}{dx^3}(1 + x)^n \bigg|_{x=-1} = n(n-1)(n-2)(1 - 1)^{n-3} = 0 \] This indicates that the sum of the coefficients multiplied by their respective powers results in zero when evaluated at \( x = -1 \). 6. **Conclusion**: Since the expression sums to zero, we conclude that: \[ S = 0 \] ### Final Answer: \[ S = 0 \]

To solve the problem, we need to evaluate the expression: \[ S = 1^3 \cdot C_1 - 2^3 \cdot C_3 - 4^3 \cdot C_4 + \ldots + (-1)^{n-1} n^3 \cdot C_n \] where \( C_r \) are the binomial coefficients from the expansion of \( (1 + x)^n \). ### Step-by-Step Solution: ...
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OBJECTIVE RD SHARMA ENGLISH-BINOMIAL THEOREM AND ITS APPLCIATIONS -Chapter Test
  1. If C(0),C(1), C(2),...,C(N) denote the binomial coefficients in the...

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  2. The term independent of x in (1+x)^(m)(1+1/x)^(n) is :

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  3. The expression [x+(x^(3)-1)^((1)/(2))]^(5)+[x-(x^(3)-1)^((1)/(2))]^(...

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  4. The coefficient of x^(53) in the expansion sum(m=0)^(100)^(100)Cm(x-3)...

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  5. If (1 + x)^(n)= C(0) + C(1) x C(2) x^(2) + …+ C(n) x^(n) , prove th...

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  6. Find the numerically grates term in the expansion of 3-5x^(15)w h e nx...

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  7. In the expansion of (1+x)^(50), find the sum of coefficients of odd po...

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  8. Find the position of the term independent of x in the expansion of (sq...

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  9. If the coefficients of x^(7) and x^(8) in the expansion of (2+x/3)^(n)...

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  10. If the rth term in the expansion of (x/3-2/x^(2))^(10 contains x^(4), ...

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  11. If the third in the expansion of [x + x^(logx)]^(6) is 10^(6) , th...

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  12. the value of x , for which the 6th term in the expansions of[2^log2sqr...

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  13. If the coefficients of (p+1)th and (P+3)th terms in the expansion of (...

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  14. about to only mathematics

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  15. The value of C(0)+3C(1)+5C(2)+7C(3)+….+(2n+1)C(n) is equal to :

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  16. Find the following sum : (1)/(n!) + (1)/(2!(n-2)!) + (1)/(4!(n-4)!)+...

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  17. The coefficient of x^(n) y^(n) in the expansion of [(1 + x)(1+y) (x...

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  18. If (1 + x - 2 x^(2))^(6) = 1 + C(1) x + C(2) x^(2) + C(3) x^(3) + …+ C...

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  19. Find the ratio of the coefficient of x^(15) to the term independent of...

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  20. Find the number of terms in the expansion of (x+y+z)^(n).

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  21. In the expansion of (1+x)^30 the sum of the coefficients of odd powers...

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