Question
Question: If (1 – x + x<sup>2</sup>)<sup>n</sup> = C<sub>0</sub> + C<sub>1</sub>x + C<sub>2</sub>x<sup>2</sup>...
If (1 – x + x2)n = C0 + C1x + C2x2 + ……….. + C2nx2n then
2n C2n – (2n – 1). C2n – 1 + ……. – C1 is equal to :
A
(n – 1) 3n–1
B
n 3n
C
(n + 1)3n+1
D
None of these
Answer
n 3n
Explanation
Solution
Differentiate the given expansion w.r.t x and put x = – 1