in the expansion of (1+3x)^n, in ascending powers of x, the third term is 252x^2. Find the positive integer value of n
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From the binomial expansion, the coefficient of the x^2 term will be
n! / ( 2! (n-2)! ) 3^2 = 252
Thus
n! / (n-2)! = 56
This is equivalent to writing
n(n-1) = 56, hence n=8
n! / ( 2! (n-2)! ) 3^2 = 252
Thus
n! / (n-2)! = 56
This is equivalent to writing
n(n-1) = 56, hence n=8
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From the binomial expansion, the coefficient of the x^2 term will be
n! / ( 2! (n-2)! ) 3^2 = 252
Thus
n! / (n-2)! = 56
This is equivalent to writing
n(n-1) = 56, hence n=8
n! / ( 2! (n-2)! ) 3^2 = 252
Thus
n! / (n-2)! = 56
This is equivalent to writing
n(n-1) = 56, hence n=8
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