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
        find the value cos(2pi/7)+cos(4pi/7)+cos(6pi/7)
4 years ago

Answers : (1)

Rinkoo Gupta
askIITians Faculty
80 Points
							cos(2pi/7)+cos(4pi/7)+cos(6pi/7)
=1/2sin(pi/7)[2sinpi/7cos2pi/7+2sinpi/7cos4pi/7+2sinpi/7cos6pi/7]
=1/2sinpi/7[sin3pi/7+sin(-pi/7) +sin5pi/7+sin(-3pi/7) +sinpi +sin(-5pi/7)]
=1/2sinpi/7[sin3pi/7-sinpi/7+sin5pi/7-sin3pi/7+0-sin5pi/7]
=1/2sinpi/7[-sinpi/7]
=-1/2
Thanks & Regards
Rinkoo Gupta
AskIITians Faculty
4 years 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

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


Get Extra Rs. 64 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