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Statement-1 sum(r=0)^(n) r ""^(n)C(r) x^...

Statement-1 `sum_(r=0)^(n) r ""^(n)C_(r) x^(r) (-1)^(r) = nx (1 - x)^(n -1)`
Statement-2:` sum_(r=0)^(n)r ""^(n)C_(r) x^(r) (-1)^(r) =0`

A

1

B

2

C

3

D

4

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze both statements and determine their validity step by step. ### Step 1: Analyze Statement 2 We start with Statement 2: \[ \sum_{r=0}^{n} r \binom{n}{r} x^r (-1)^r = 0 \] Using the identity for \( r \binom{n}{r} = n \binom{n-1}{r-1} \), we can rewrite the left-hand side: \[ \sum_{r=0}^{n} r \binom{n}{r} x^r (-1)^r = n \sum_{r=1}^{n} \binom{n-1}{r-1} x^r (-1)^r \] Changing the index of summation by letting \( k = r - 1 \), we have: \[ = n \sum_{k=0}^{n-1} \binom{n-1}{k} x^{k+1} (-1)^{k+1} \] This can be simplified further: \[ = -n x \sum_{k=0}^{n-1} \binom{n-1}{k} x^k (-1)^k \] Using the Binomial Theorem, we know: \[ \sum_{k=0}^{n-1} \binom{n-1}{k} (-x)^k = (1 - x)^{n-1} \] Thus, we have: \[ -n x (1 - x)^{n-1} \] Setting this equal to zero gives us: \[ -n x (1 - x)^{n-1} = 0 \] This is true for \( x = 0 \) or \( x = 1 \), or for any \( n \) when \( x \) is in the range [0, 1]. Therefore, Statement 2 is **true**. ### Step 2: Analyze Statement 1 Now we check Statement 1: \[ \sum_{r=0}^{n} r \binom{n}{r} x^r (-1)^r = n x (1 - x)^{n-1} \] From our previous calculation, we found that: \[ \sum_{r=0}^{n} r \binom{n}{r} x^r (-1)^r = -n x (1 - x)^{n-1} \] This is not equal to \( n x (1 - x)^{n-1} \) since it has a negative sign. Therefore, Statement 1 is **false**. ### Conclusion - Statement 1 is false. - Statement 2 is true. ### Final Answer Thus, the correct answer is that Statement 1 is false and Statement 2 is true. ---

To solve the problem, we need to analyze both statements and determine their validity step by step. ### Step 1: Analyze Statement 2 We start with Statement 2: \[ \sum_{r=0}^{n} r \binom{n}{r} x^r (-1)^r = 0 \] Using the identity for \( r \binom{n}{r} = n \binom{n-1}{r-1} \), we can rewrite the left-hand side: ...
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Statement-1: sum_(r=0)^(n) (1)/(r+1) ""^(n)C_(r) = (1)/((n+1)x) {( 1 + x)^(n+1) -1}^(-1) Statement-2: sum_(r=0)^(n) (""^(n)C_(r))/(r+1) = (2^(n+1))/(n+1) .

Statement -2: sum_(r=0)^(n) (-1)^( r) (""^(n)C_(r))/(r+1) = (1)/(n+1) Statement-2: sum_(r=0)^(n) (-1)^(r) (""^(n)C_(r))/(r+1) x^(r) = (1)/((n+1)x) { 1 - (1 - x)^(n+1)}

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sum_(r=0)^(n)(""^(n)C_(r))/(r+2) is equal to :

If x + y = 1 , prove that sum_(r=0)^(n) r""^(n)C_(r) x^(r ) y^(n-r) = nx .

Let a, b, c be the sides of Delta ABC opposite to angles A, b,C respecitvely. Let alpha = sum_(r=0)^(n) ""^(n)C_(r) b^(n-r) c^(r) cos{rB - (n-r)C} and beta = sum_(r=0)^(n) ""^(n)C_(r) b^(n-r) c^(r) sin{rB - (n-r)C} Statement -1: alpha = alpha^(n) Statement-2: beta = alpha^(n)

sum_(r = 0)^(n-1) (C_r)/(C_r + C_(r+1)) =