Badiuddin askIITians.ismu Expert
Last Activity: 14 Years ago
Dear manan
from Binomial expansion we know that
(1+x)n =C0 + C1x + C2x2 +C3x3 +C4x4+C5x5+ ......Cnxn
now differentiate both side
n(1+x)n-1 = C1 +2C2x+3C3x2 +4C4x3 + 5C5x4 + ......
now put x=1
n2n-1 = C1 +2C2+3C3 +4C4 + 5C5 + ...... .............(1)
now put x=-1
0 =C1 -2C2+3C3 -4C4 + 5C5 + ...... .............(2)
(1) +(2)
n2n-2 = C1 +3C3 + 5C5 + ...... ............
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Badiuddin