(1+x)n = C0+C1x + C2x2+....+ Cnxn
puting x= 2
and again putting x= -2 and subtracting the two obtained equations we get
3n-(-1)n2= 2C1 +23C3+...+2nCn
If C0, C1, C2, ........., Cn are the binomial coefficients, then
2 C 1 + 2 3 C 3 + 2 5 C 5 +............... equals
(a) 3 n + (-1) n2 (b)3n - (-1) n2
(c) 3 n +12 (d)3 n -12
(1+x)n = C0+C1x + C2x2+....+ Cnxn
puting x= 2
and again putting x= -2 and subtracting the two obtained equations we get
3n-(-1)n2= 2C1 +23C3+...+2nCn