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

Vectors

Cool goIITian

Joined:	25 May 2008
Post:	71

8 Jun 2008 13:57:13 IST

0 People liked this

474

find d angle b'ween d vectors joining to P1(1,2,3) and P2(2,-3,-1)

None

find d angle b'ween d vectors joining to P1(1,2,3) and P2(2,-3,-1)

Share this article on:

Comments (4)

'',' Off to a nu start!!

Blazing goIITian

Joined: 13 Jan 2007

Posts: 1289

8 Jun 2008 14:00:12 IST

Like 0 people liked this

60 degree.
cos theta = a.b/|a|.|b|

MAQ MAK

New kid on the Block

Joined: 6 Jun 2008

Posts: 21

8 Jun 2008 14:05:06 IST

Like 0 people liked this

P1.P2/|P1||P2| is coming out to be -1/2... Hence d angle must be 120 degrees starting from P1 and ending in P2...

Swarna

Cool goIITian

Joined: 25 May 2008

Posts: 71

8 Jun 2008 14:06:28 IST

Like 0 people liked this

CAN U SHOW D WORKING

MAQ MAK

New kid on the Block

Joined: 6 Jun 2008

Posts: 21

8 Jun 2008 14:10:56 IST

Like 0 people liked this

P1.P2 = ( i + 2j + 3k ).(2i -3j -k ) = 1.2 - 2.3 - 3.1 = -7
|P1|.|P2| = (rt 14).(rt 14) = 14
cos(theta) = -7/14 = -1/2 => theta = 120 degrees...

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

Find Posts by Topics

Physics.

Topics

9396

20092

3672

2186

7617

2827

2638

Mathematics.

Chemistry.

Biology

Institutes

Parents

Board

Fun Zone