the coefficient of x^k in expansion E= 1+(1+x)+(1+x)^2+ (1+x)^n is - Maths - Binomial Theorem

Question

the coefficient of x^k in expansion E= 1+(1+x)+(1+x)^2+ (1+x)^n is?

Ajay · Answer

There is also an another approach by taking the series as
geometrical progression , but this would also yield the same result
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the coefficient of x^k in expansion E= 1+(1+x)+(1+x)^2+....(1+x)^n is?