 Click to Chat

1800-1023-196

+91-120-4616500

CART 0

• 0

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

if in triangle ABC a=6,b=3 and cos(A-B)=4/5 then its area is

one year ago

Dear Hemant

cos (A-B) = (1 -tan²(A-B)/2)/(1+tan²(A-B)/2) = 4/5
On cross multiplication and then solving

tan²(A-B)/2 = 1/9
tan(A-B)/2 = 1/3

Hence
(a-b) cot(C/2)/(a+b) = 1/3
On solving

Cot(c/2) = 1
C/2 = 45°
C = 90°
Hence it is a right angle triangle

Now area = (1/2)*3*6 = 9 square units

Regards
Arun (askIITians forum expert)
one year ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies

Other Related Questions on Trigonometry

View all Questions »  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