Home » Ask & Discuss » Mathematics. » Trignometry « Back to Discussion



Trignometry

anchit saini's Avatar
Blazing goIITian

Joined: 1 Feb 2008
Post: 1251
27 Mar 2008 09:47:48 IST
0 People liked this
5
598 View Post
easy qn
None

In an isosceles triangle ABC , AB = AC

Suppose angular bisector of B  meets AC at point D and

BC = BD + AD

Find the measure of angle A


Share this article on:

Comments (5)

anchit saini's Avatar

Blazing goIITian

Joined: 1 Feb 2008
Posts: 1251
27 Mar 2008 10:15:39 IST
0 people liked this

no attempt
??

Sad
gokul subramanian's Avatar

Blazing goIITian

Joined: 28 Jan 2008
Posts: 1451
27 Mar 2008 11:31:02 IST
0 people liked this

solve the eqn:
sin3@/sin2@  = 1+ (sin@/sin4@)
where A=180-4@
anchit saini's Avatar

Blazing goIITian

Joined: 1 Feb 2008
Posts: 1251
27 Mar 2008 13:10:56 IST
0 people liked this

pls someone give the complete soln
anchit saini's Avatar

Blazing goIITian

Joined: 1 Feb 2008
Posts: 1251
27 Mar 2008 19:19:11 IST
0 people liked this

anyone ??
The Werewolf's Avatar

Blazing goIITian

Joined: 22 Mar 2008
Posts: 385
27 Mar 2008 20:53:57 IST
1 people liked this

Imagine the figure in your mind

Applying sin law in triangle DBC we have

BD/sinheta = BC/sin (pi-3heta/2) =>[BD/sinheta]sin (pi-3heta/2) = BC....(i)

Apply sine law in triangle ADB we have

AD =[sinheta/2/sin(pi-2heta)] BD......(ii)

subsitute values of BC and BD from equation (i) and (ii) in BC= BD+AD

we get,

[BD/sinheta]sin (pi-3heta/2) = BD + [sinheta/2/sin(pi-2heta)] BD

BD gets cancelled from both sides , solve for heta




Quick Reply


Reply

Some HTML allowed.
Keep your comments above the belt or risk having them deleted.
Signup for a avatar to have your pictures show up by your comment
If Members see a thread that violates the Posting Rules, bring it to the attention of the Moderator Team
Free Sign Up!

Preparing for IIT-JEE ?

Arihant Revision Package for IIT JEE - Books, Practice Tests + Rank Predictor


@ INR 1,995/-

For Quick Info

Name

Mobile No.

Find Posts by Topics

Physics.

Topics

Mathematics.

Chemistry.

Biology

Parents

Board

Fun Zone

Sponsored Ads