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
        in sequence 1,2,2,3,3,3,4,4,4,4,5,5,5,5,5.........

find 150th term
7 years ago

Answers : (2)

Anantha Krishnan
18 Points
							

Hope this will help you ,

this series can be converted into an easier one if we write the frequencies of the given nos. 

let'' start with a smaller no. , say the 5th term. 

thus, the cumulative frequency of nth no. will be the sum of the n terms,i.e., {n(n+1)}/2.

so, coming to our example, equating 7 to the sum given:-

5= {n(n+1)}/2  or n2 +n -10=0

this gives:- n= [-1+(1+40)1/2]/2     {since n cannot be -ve, so +ve sqrt.}

this gives, 3>n>2.   thus,  the cumulative frequency of 2 is less than 5 and that of 3 is more than 5.  so, n=3.  which is correct 

now, coming back to the problem , we equate 150 to the sum given  

thus, 150= {n(n+1)}/2 or n2 +n - 300=0 

Now factorise and conside the +ve root and not the -ve root .


7 years ago
Anantha Krishnan
18 Points
							

Didn''t it help you?

7 years 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