MCQ
$\left\{C_0+2 C_1+3 C_2+\ldots+(n+1) C_n\right\}=?$
  • A
    $( n +1). 2^{ n }$
  • B
    $( n +2) . 2^{ n +1}$
  • $( n +2). 2^{ n -1}$
  • D
    $n . 2^{ n -1}$

Answer

Correct option: C.
$( n +2). 2^{ n -1}$
Here, $C _0+2 C _1+3 C _2+\ldots+( n +1) C _{ n }$
$=\left(C_0+C_1+C_2+\ldots+C_n\right)+\left(C_1+2 C_2+3 C_3+\ldots+n C_n\right)$
$=2^n+n \cdot 2^{n-1}$
$=(n+2) \cdot 2^{n-1}$

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