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
        
The coefficient of x^3 in the expansion of (1+3x)^2 / 1-2x will be?
Ans: 50
2 months ago

Answers : (2)

Aditya Gupta
1690 Points
							
we know thw identity: (1 – y)^(-1)= 1+y+y^2+y^3+..................
so,  (1+3x)^2 / (1-2x )=  (1+3x)^2*(1 – 2x)^(-1)= (1+6x+9x^2)*(1+2x+4x^2+8x^3+.........)
so, coeff of x^3 is 1*8 + 6*4 + 9*2= 26+24
50
kindly approve :)
2 months ago
Arun
22770 Points
							
Dear student
 
it can be written as 
( 1 + 9x^2 + 6x) (1 – 2x)^-1
 
 = ( 1 + 9x^2 + 6x) ( 1 + 2x + 4x^2 + 8x^3+ …..)
 
hence coefficient of x3 = 8 + 18 + 24 = 50
2 months ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies


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

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


Ask Experts

Have any Question? Ask Experts

Post Question

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