Question
Question: In the expansion of (x + a)<sup>n</sup>, the sum of even terms is E and that of odd terms is O, then...
In the expansion of (x + a)n, the sum of even terms is E and that of odd terms is O, then O2 – E2 is equal to –
A
(x2 + a2)n
B
(x2 – a2)n
C
(x – a)2n
D
None
Answer
(x2 – a2)n
Explanation
Solution
Let (x + a)n = O + E then (x – a)n = O. – E
Now O2 – E2 = (O + E) (O – E) = (x + a)n (x–a)n
= (x2 – a2)n