Let S1 = nC0 + nC1 + nC2.............nCn and S2 = nC0 - nC1 + nC2 ..............+ (−1)n nCn
Find the value of S1S1+S2 is
Consider the expansion of (1+x)n
(1+x)n = nC0 + nC1x + nC2x2 ...............nCcxn
When we put x = 1, we get S1 and when we put x = -1, we get S2
⇒ S1 = nC0 + nC1 + nC2 ........nCn = 2n
S2 = nC0 - nC1 + nC2 ........= 0
⇒ S1S1+S2 = S1S1 = 1