csat-suneung 2010 Q19

csat-suneung · South-Korea · csat__math-humanities 3 marks Binomial Theorem (positive integer n) Determine Parameters from Conditions on Coefficients or Terms

In the expansion of the polynomial $( 1 + x ) ^ { n }$, the coefficient of $x ^ { 2 }$ is 45. Find the natural number $n$. [3 points]

In the expansion of the polynomial $( 1 + x ) ^ { n }$, the coefficient of $x ^ { 2 }$ is 45. Find the natural number $n$. [3 points]