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: 11
        
The value of  tan(pi/12) + 2tan(2 pi/12) + 4tan(4 pi/12) + 
8cot(8 pi/12) ,is.   Ans: cot (pi /12)
 
2 months ago

Answers : (4)

Arun
17816 Points
							
Dear student
 
I want you to remember this-
 
tan A + 2 tan 2A + 4 tan4A + 8cot 8A = cot A
 
Hence for the above question, A = pi/12
 
Hence answer will be cot pi/12
2 months ago
Heisenberg
12 Points
							
But sir can you prove that part where you said that the result is important?
remembering so many formulae plus so many results is a had job......
 
 
 
2 months ago
Arun
17816 Points
							
Dear student
 
I am giving you some hint you can solve this then,
 
take 8 cot 8A now open this in the form of tan 4A 
 
after this you will clearly find ome common in terms one by one from right to left. and final result will be cot A
2 months ago
Aditya Gupta
823 Points
							
heisenberg an even better way to solve is to use the identity tanx= cotx – 2cot2x
note that the rth term of summation is 2^(r-1)tan(2^(r-1)y) where y is pi/12.
write it as 2^(r-1)[cot(2^(r-1)y) – 2cot2^ry]
= 2^(r-1)cot(2^(r-1)y) – 2^rcot2^ry, which is easily seen to telescope!
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

  • 31 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