KCET2009MathematicsBinomial Theorem
If f ( x )=1+ nx + n ( n -1) 2 x ²+ n(n-1)(n-2) 6 x³+ +x^ n then f ^ (1) is equal to
Options
- An ( n -1) 2^ n -1
- B(n-1) 2^ n-1
- Cn(n-1) 2^ n-2
- Dn(n-1) 2^ n
Correct answer
C. n(n-1) 2^ n-2
Step-by-step solution
Given, f ( x )=1+ nx + n ( n -1) 2 ! x ²+ n ( n -1)( n -2) 3 ! x ³+ + x ^ n array ll & f ( x )=(1+ x )^ n & f ^ ( x )= n (1+ x )^ n -1 & f ^ ( x )= n ( n -1)(1+ x )^ n -2 & f ^ (1)= n ( n -1) 2^ n -2 array