NCERT Class 11-Math՚s: Chapter – 8 Binomial Theorem Part 7 (For CBSE, ICSE, IAS, NET, NRA 2023)

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Question 10:

If the coefficient of second, third and fourth terms in the expansion of are in A. P. Show that .

Answer:

Given expression are in A. P. , show that

Coefficient of second term

Coefficient of third term

and Coefficient of fourth term

As the given condition, and are in A. P.

Hence proved.

Question 11:

Find the coefficient of in the expansion of .

Answer:

Long Answer Type

Question 12:

If is a real number and if the middle term in the expansion of is , find .

Answer:

Given expression is

Number of terms

Middle term

Now

Hence, the required value of

Question 13:

Show that the middle term in the expansion of is

Answer:

Given expression is

Number of terms (odd)

Middle term

General Term

Hence, the middle term