NDA2023MathematicsBinomial TheoremActual
Let (1+x)^n=1+T₁ x+T₂ x^2+T₃ x^3+ +T_n x^n What is T₁+2 T₂+3 T₃+ +n T_n equal to?
Options
- A0
- B1
- C2^ n
- Dn 2^ n-1
Correct answer
D. n 2^ n-1
Step-by-step solution
aligned & Given, (1+ x )^ n =1+ T ₁ x + T ₂ x ^2+ .+ T _ n x ^ n & differentiating both side with respect to x , we get & n (1+ x )^ n -1 = T ₁+2 ~T ₂ x ^1+2 ~T ₃ x ^2+ .+ nT _ n x ^ n -1 ( i ) & n (1+1)^ n -1 = T ₁+2 ~T ₂+3 ~T ₃+ .+ nT _ n & . T ₁+2 ~T ₂+3 ~T ₃+ .+ nT _ n = n ^ n -1 Putting x =1 aligned