MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: Rs.

There are no items in this cart.
Continue Shopping
Menu
Grade: 12th pass
        
find the greatest term in the expansion of (7-5x)^11 when x=2/3
14 days ago

Answers : (1)

Arun
16143 Points
							
Dear Sara
 
use the formula
 
n+ 1 / 1 + |a/b| = 12 / (31/10) = 120/31 = 3._____
 
hence 4th term is greatest
 
or you can also solve like this
Binomial expansion of (7 - 5 x)¹¹    when x = 2/3
ie.,   (7 - 10/3)¹¹ = (21 - 10)¹¹ / 3¹¹
We consider the binomial expansion of (21 - 10)¹¹.
In the expansion alternate terms are negative. So we take only positive terms.
21¹¹,  ¹¹C₂ 21⁹ 10²,  ¹¹C₄ 21⁷ 10⁴,  ¹¹C₆ 21⁵  10⁶,  ¹¹C₈ 21³ 10⁸, ¹¹C₁₀ 21 10¹⁰
We take ratios of T0/T2, T2/T4, T4 / T6 ... Then we find that 21²/10² is there in every ratio. Its value is 4.41.  These ratios are:
4.41/55,  4.41/6 ,  4.41*5/7,  14/5,  15
So T0 T6, T6 > T8, T8 > T10
So T4 is maximum.  It is   ¹¹C₄ 21⁷ 10⁴ / 3¹¹
 
14 days ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies

Get Extra Rs. 1,590 off

COUPON CODE: SELF10


Course Features

  • 731 Video Lectures
  • Revision Notes
  • Previous Year Papers
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Test paper with Video Solution


Course Features

  • 101 Video Lectures
  • Revision Notes
  • Test paper with Video Solution
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Previous Year Exam Questions


Get Extra Rs. 233 off

COUPON CODE: SELF10

Ask Experts

Have any Question? Ask Experts

Post Question

 
 
Answer ‘n’ Earn
Attractive Gift
Vouchers
To Win!!! Click Here for details