Question
Question: If (1 + x) (1+ x + x2)(1 + x + x2 + x3).......... (1 + x + x2 + x3 +...+ xn) = a0 + a1x + a2x2 + .....
If (1 + x) (1+ x + x2)(1 + x + x2 + x3)..........
(1 + x + x2 + x3 +...+ xn) = a0 + a1x + a2x2 + ....+ amxm then ∑r=0mar=
A
1
B
n
C
n + 1!
D
n!
Answer
n!
Explanation
Solution
(1 + x) (1 + x + x2) (1+ x + x2 + x3) ....(1 + x + x2 +....xn)
= a0 + a1x + a2x2 +.....+amxm
substituting x = 1
1 × (2) (3) (4)........ (n) = ∑r=0mar= n!