Home » Ask & Discuss » Mathematics. » Analytical Geometry « Back to Discussion

Analytical Geometry

Blazing goIITian

Joined:	4 Nov 2007
Post:	1524

11 Nov 2007 14:27:08 IST

0 People liked this

335

a few more questions...

None

i) if l₁, m₁, n₁ and l₂,m₂,n₂are the direction cosines of 2 mutually perpendicular lines, show that the direction cosinesof line perpendicular to both of these are m₁n₂-m₂n₁,n₁l₂-n₂l₁,l₁m₂-l₂m₁.

ii) find the eqn of a line II^l to x axis and passing thru origin

iii) if coordinates of a pt A,B,C, AND D be(1,2,3) ,(4,5,7) ,(-4,3,-6) and(2,9,2), then find angle b/w AB and CD.

Share this article on:

Comments (4)

sankydreams

Blazing goIITian

Joined: 14 May 2007

Posts: 822

11 Nov 2007 16:26:09 IST

Like 1 people liked this

How can there be a line parallel to x axis and passing thru origin, it can only be x axis itself.....

joy francis

Blazing goIITian

Joined: 19 Feb 2007

Posts: 1802

11 Nov 2007 16:30:10 IST

Like 0 people liked this

i) just find the cross product of the given vectors and find it's dcs.

joy francis

Blazing goIITian

Joined: 19 Feb 2007

Posts: 1802

11 Nov 2007 16:34:21 IST

Like 1 people liked this

iii) AB vector is : 3i+3j+4k

CD vector is : 6i+6j+8k

if @ is the angle b/w the two

cos@ = 68/root(4624)

Ashwini

Blazing goIITian

Joined: 4 Nov 2007

Posts: 1524

11 Nov 2007 18:57:21 IST

Like 0 people liked this

but the ans 4 iii) is cos^-1 ( 5/ root 187)

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