CBSE CLASS XI
Q.1. Find . Hence, Evaluate .
Q.2. Show that 9n+1 – 8n -9 is divisible by 64.
Q.3. Find a if the 17th and 18th terms of the expansion of (2 + a)50 are equal.
Q.8. Find the coefficient of in the product (1 + 2x)6 (1 – x)7 using binomial theorem.
Q.9. Find the rth term from the end in the expansion of (x + a)n.
Q.10. Find the expansion of using binomial theorem.
Q.11. In the expansion of (1+a)m+n, prove that coefficients of am and an are equal.
Q.12. The second, third and fourth terms in the binomial expansion of (x + a)n are 240, 720 and 1080 respectively. Find x, a and n.
Q.13. If the coefficients of in the expansion of the (1 + a)n are in arithmetic progression, prove that n2 - n(4r +1) + 4 r2 – 2 = 0.
Q.14. The coefficients of the (r – 1)th , rth and (r + 1)th terms in the expansions of (x +1)n are in the ratio of 1 : 3 : 5. Find n and r.
Q.15. Find n if the ratio of the 5 th term from the beginning to the 5 th term from the end
Paper By Mr. Anil Kumar Tondak