badge image

Enroll For Free Now & Improve Your Performance.

×
User Icon
User Icon
User Icon
User Icon
User Icon

Thank you for registering.

One of our academic counsellors will contact you within 1 working day.

Please check your email for login details.
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

                        

If 32 sin^6 x = 10 - 15cos2x + b cos4x - a cos6x then prove , tan x tan5x = (a+b-5)/(a-b+7)

5 years ago

Answers : (1)

Imrul Kayes
20 Points
							
32 sin^6x = 4.(2sin^2 x)^3 = 4(1- cos2x)^3 = 4(1-cos^3 2x -3cos 2x +3cos^2 2x) = 4- 12cos 2x + 6(1+cos 4x) – (cos 6x+ 3cos2x) = 10 – 15cos 2x +6cos 4x -cos6x
then,
10- 15cos 2x +6cos 4x – cos 6x =10 – 15cos2x + b cos4x – a cos6x
or, (6-b)cos4x = (1-a)cos6x
or,cos4x/cos6x = (1-a)/(6-b)
or, (cos4x – cos 6x)/(cos 4x + cos6x) = (1-a-6+b)/(1-a+6-b)
or, tan5x tanx =(-a+b-5)/(7-a-b)
this isthe correct answer due to the minus sign in the question before acos6x. it should  be + sign to get the mentioned answer.
5 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

  • 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