Let n N. If (1+x)^ n =a_0+a_1x+a_2x^2+ +a_nx^ n , and a_ n-3 ,a_ n-2 ,a_ n-1 are in AP then

JEE Advanced Mathematics question

Let . If , and are in AP then

Answer: (A),(C)

Since : , , . So the condition says — i.e. — are in AP. (a) ✔.

Solve ():

n(n-1)=n+\ ⇒\ 6(n-1)=6+(n-1)(n-2)\ ⇒\

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Question ID VK-108360