In the expansion of (1 + x) + (1 + x) ^ 2 + (1 + x) ^ 3 +... + (1 + x) ^ n, the coefficient of term x ^ 4 is?

In the expansion of (1 + x) + (1 + x) ^ 2 + (1 + x) ^ 3 +... + (1 + x) ^ n, the coefficient of term x ^ 4 is?

(1+x)+(1+x)^2+(1+x)^3+...+(1+x)^n=[(1-(1+x)^(n+1)]/(1-(1+x)]=[(1+x)^(n+1)-1]/x
Coefficient of x ^ 4 in =)] = (1 + x) ^ (n + 1) coefficient of x ^ 5 in (n + 1,5)

Elden Ring Premiere

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