Home
Class 11
MATHS
1^(2). C(1) - 2^(2) . C(2)+ 3^(2). C(3) ...

`1^(2). C_(1) - 2^(2) . C_(2)+ 3^(2). C_(3) -4^(2)C_(4) + ...+ (-1).""^(n-2)n^(2)C_(n)=`

A

0

B

`2^(n)`

C

`n2^(n-1)`

D

`-n2^(n - 1)`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the expression \( 1^2 C_1 - 2^2 C_2 + 3^2 C_3 - 4^2 C_4 + \ldots + (-1)^{n-2} n^2 C_n \), we can use the Binomial Theorem and properties of binomial coefficients. ### Step-by-Step Solution: 1. **Understanding the Binomial Expansion**: The binomial expansion of \( (1 + x)^n \) is given by: \[ (1 + x)^n = C_0 + C_1 x + C_2 x^2 + \ldots + C_n x^n \] where \( C_k = \binom{n}{k} \). 2. **Substituting \( x = -1 \)**: If we substitute \( x = -1 \) into the binomial expansion, we have: \[ (1 - 1)^n = 0 \] This gives us: \[ C_0 - C_1 + C_2 - C_3 + \ldots + (-1)^n C_n = 0 \] 3. **Rearranging the Terms**: Rearranging the above equation, we can express it as: \[ C_1 - C_2 + C_3 - C_4 + \ldots + (-1)^{n-1} C_n = C_0 \] 4. **Differentiating the Binomial Expansion**: Now, we differentiate the binomial expansion with respect to \( x \): \[ \frac{d}{dx}[(1 + x)^n] = n(1 + x)^{n-1} \] The derivative of the right-hand side gives: \[ C_1 + 2C_2 x + 3C_3 x^2 + \ldots + nC_n x^{n-1} \] 5. **Substituting \( x = -1 \) Again**: Now substituting \( x = -1 \) into the differentiated equation: \[ n(1 - 1)^{n-1} = 0 \] This gives: \[ C_1 - 2C_2 + 3C_3 - 4C_4 + \ldots + (-1)^{n-1} n C_n = 0 \] 6. **Multiplying by \( x \)**: To find the expression \( 1^2 C_1 - 2^2 C_2 + 3^2 C_3 - 4^2 C_4 + \ldots \), we can multiply the previous result by \( x \) and differentiate again: \[ \frac{d^2}{dx^2}[(1 + x)^n] = n(n-1)(1 + x)^{n-2} \] The second derivative gives: \[ C_1 + 4C_2 x + 9C_3 x^2 + \ldots + n^2 C_n x^{n-1} \] 7. **Final Evaluation**: Substituting \( x = -1 \) again, we find: \[ n(n-1)(1 - 1)^{n-2} = 0 \] Thus, the expression simplifies to: \[ 1^2 C_1 - 2^2 C_2 + 3^2 C_3 - 4^2 C_4 + \ldots + (-1)^{n-2} n^2 C_n = 0 \] ### Conclusion: The final result of the expression is: \[ \boxed{0} \]

To solve the expression \( 1^2 C_1 - 2^2 C_2 + 3^2 C_3 - 4^2 C_4 + \ldots + (-1)^{n-2} n^2 C_n \), we can use the Binomial Theorem and properties of binomial coefficients. ### Step-by-Step Solution: 1. **Understanding the Binomial Expansion**: The binomial expansion of \( (1 + x)^n \) is given by: \[ (1 + x)^n = C_0 + C_1 x + C_2 x^2 + \ldots + C_n x^n ...
Promotional Banner

Topper's Solved these Questions

  • BINOMIAL THEOREM AND ITS APPLCIATIONS

    OBJECTIVE RD SHARMA ENGLISH|Exercise Section I - Solved Mcqs|100 Videos
  • BINOMIAL THEOREM AND ITS APPLCIATIONS

    OBJECTIVE RD SHARMA ENGLISH|Exercise Section I - Assertion Reason Type|13 Videos
  • CARTESIAN CO-ORDINATE SYSTEM

    OBJECTIVE RD SHARMA ENGLISH|Exercise Exercise|27 Videos

Similar Questions

Explore conceptually related problems

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

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)=

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

Evaluate .^(n)C_(0).^(n)C_(2)+2.^(n)C_(1).^(n)C_(3)+3.^(n)C_(2).^(n)C_(4)+"...."+(n-1).^(n)C_(n-2).^(n)C_(n) .

Find .^(n)C_(1)-(1)/(2).^(n)C_(2)+(1)/(3).^(n)C_(3)- . . . +(-1)^(n-1)(1)/(n).^(n)C_(n)

Prove that (n-1)^(2) C_(1) + (n-3)^(2) C_(3) + (n-5)^(2) C_(5) . + ….= n (n+1)2^(n-3) , where C_(r) stands for ""^(n)C_(r) .

If (1 + x)^(n) = C_(0) + C_(1) x + C_(2) x^(2) + …+ C_(n) x^(n) , prove that C_(0) C_(n) - C_(1) C_(n-1) + C_(2) C_(n-2) - …+ (-1)^(n) C_(n) C_(0) = 0 or (-1)^(n//2) (n!)/((n//2)!(n//2)!) , according as n is odd or even .

STATEMENT - 1 : If n is even, .^(2n)C_(1)+.^(2n)C_(3)+.^(2n)C_(5)+"….."+.^(2n)C_(n-1) = 2^(2n-2) . STATEMENT - 2 : .^(2n)C_(1) + .^(2n)C_(3)+ .^(2n)C_(5) + "……"+ .^(2n)C_(2n-1) = 2^(2n-1)

If (1 + x)^(n) = C_(0) + C_(1) x + C_(2) x^(2) + …+ C_(n) x^(n) , prove that C_(0)^(2) - C_(1)^(2) + C_(2)^(2) -…+ (-1)^(n) *C_(n)^(2)= 0 or (-1)^(n//2) * (n!)/((n//2)! (n//2)!) , according as n is odd or even Also , evaluate C_(0)^(2) - C_(1)^(2) + C_(2)^(2) - ...+ (-1)^(n) *C_(n)^(2) for n = 10 and n= 11 .

Prove that: (i) r.^(n)C_(r) =(n-r+1).^(n)C_(r-1) (ii) n.^(n-1)C_(r-1) = (n-r+1) .^(n)C_(r-1) (iii) .^(n)C_(r)+ 2.^(n)C_(r-1) +^(n)C_(r-2) =^(n+2)C_(r) (iv) .^(4n)C_(2n): .^(2n)C_(n) = (1.3.5...(4n-1))/({1.3.5..(2n-1)}^(2))

OBJECTIVE RD SHARMA ENGLISH-BINOMIAL THEOREM AND ITS APPLCIATIONS -Chapter Test
  1. 1^(2). C(1) - 2^(2) . C(2)+ 3^(2). C(3) -4^(2)C(4) + ...+ (-1).""^(n-2...

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

  14. about to only mathematics

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |