Can neone pls explain how
n{1+(n-1)+(n-1)(n-2)1.2+...........+1}
=n.2n-1 ?
AND
nx{1+(n-1)x+(n-1)(n-2)1.2x2+........+xn-1}
=nx(1+x)n-1 ?
Pleaaaaaaaase do explain this...
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2 Answers
3the first 1 is ...
nC1 + 2nC2 + 3nC3 ................!!!
now we know ..
(1+x)^n = nC0 + nC1x^1 + .......................
d(1+x)^n/dx = 1nC1 + 2xnC2 +......................
n(1+x)^n-1 = the shit ....
put x = 1...
n2^n-1 = the stuff!!!!!!!
3now that u know the first 1 ... the second 1 u just integrate instead of differentiating .... try it ............
