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: 10
        (1-cosectheta)(1-sectheta)(1+cosectheta)(1+costheta)=costheta
2 years ago

Answers : (1)

Sreevignesh
22 Points
							
I can't insert theta... So I am using x instead of theta
(1-cosec x ) ( 1-sec x) (1+cosec x ) ( 1+cos x)  
=    (1-cosec x ) ( 1+ cosec x) (1- 1/cos x) ( 1+ cos x)
=     (1 - cosec ² x) [ ( cos x -1 )/ cos x] ( 1+ cos x ).  [ using (a+b)( a- b)= a²+b²
                                                                                            and taking LCM]
=    (- cot ² x) ×  [( cos ²x -1 ) /cos x].        [ multiply using ( a+b) ( a- b)=a²+b²
                                                                      And   1+ cot ²x = cosec ²x]
=     (- cos ²x )/(sin ²x) × (- sin ²x)/ cos x.     [ cot x = cos x /sin x]
=     cos x                                                                          [ sin ²x+ cos ²x =1 ]
On cancelling , sin²x will be removed 
                           Two - signs will become + and
                           Only one cos x will be there
         Hence it is proved
 
2 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