help with vectors

Thread Starter

Omega

Joined Feb 23, 2009
15
Hello every one I have this vector relation
E=A+\(\alpha\)(HXA) where E,A and H are vectors I want to proof that A=(E-\(\alpha\)(HXA))/\(\sqrt{1+H^{2}\alpha^{2}}\)
any one remeber how we can do this using vector identities or simple geometry or both of them (may be)?
 

Ratch

Joined Mar 20, 2007
1,070
Omega,

Just so there is not doubt, define what the capital H and alpha, both under the square root sign mean.

Ratch
 

Mark44

Joined Nov 26, 2007
628
Hello every one I have this vector relation
E=A+\(\alpha\)(HXA) where E,A and H are vectors I want to proof that A=(E-\(\alpha\)(HXA))/\(\sqrt{1+H^{2}\alpha^{2}}\)
any one remeber how we can do this using vector identities or simple geometry or both of them (may be)?
Starting with E=A+\(\alpha\)(HXA),
subtract \(\alpha\)(HXA) from both sides, which gives you
A=(E-\(\alpha\)(HXA))

I have no idea how you got the radical in there that you show.
 

Thread Starter

Omega

Joined Feb 23, 2009
15
sorry the correct equation is A=(E-
(HXE))/(1+\(\alpha\)\(^{2}\)H\(^{2}\)) I am realy sorry for this mistake. both of E and H are vectors with magnitudes E and H respectively and \(\alpha\) is just a constant
I tried the method of Mark44 but it did not give me the factor 1/(1+\(\alpha\)\(^{2}\)H\(^{2}\))
 

Ratch

Joined Mar 20, 2007
1,070
Omega,

Sorry the correct equation is A=(E-(HXE))/(1+H)
Is this correcting the first or the second equation of your problem? You really should completely restate the problem after checking it carefully for typos and other errors so we don't have to guess what it means.

Ratch
 

Thread Starter

Omega

Joined Feb 23, 2009
15
ok from the begining: it is given that E=A+
(HXA) I need to proof the expression:
A=(E-
(HXE))/(1+
H
) where A, E, and H are vectors and H is the magnitude of H and
is just a constant
 

killerfish

Joined Feb 27, 2009
29
Hi guys,

currently im teaching myself vector, any of u guys could recommend good online sites that teach vectors from stretch to advance? I did a google around, i couldnt find any site cover in-depth/details about it rather just brief one. And I couldnt get any course notes to help me.:( Hope u guys lent me a hand.

Thanks.
 
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