UrgentAndrey Posted July 19, 2012 Share Posted July 19, 2012 Hello everyone, Great forum, wondering if you can help me with a problem. Ive attached the question along with my calculations so far. Any help would be fantastic Link to comment Share on other sites More sharing options...
ajb Posted July 19, 2012 Share Posted July 19, 2012 Your equation 2 is correct, but how you got to it is not. You cannot divide by a vector in the way you have. I think all the question is asking you to do is work out the scalar product in 2d. The answer should be just a number. Link to comment Share on other sites More sharing options...
UrgentAndrey Posted July 19, 2012 Author Share Posted July 19, 2012 Your equation 2 is correct, but how you got to it is not. You cannot divide by a vector in the way you have. I think all the question is asking you to do is work out the scalar product in 2d. The answer should be just a number. Hi ajb, So using the information I have, how can I obtain a value for V^mu ?? Is there something simple I'm missing? Hi ajb, So using the information I have, how can I obtain a value for V^mu ?? Is there something simple I'm missing? It simply isn't a case of: V^ mu = V^nu is it? In which case V^mu = (3,1) Link to comment Share on other sites More sharing options...
studiot Posted July 19, 2012 Share Posted July 19, 2012 I am unsure of your convention. What are you signifying by upper and lower are they transposed? Link to comment Share on other sites More sharing options...
UrgentAndrey Posted July 19, 2012 Author Share Posted July 19, 2012 Well according to ajb it looks as if I have to find the scalar product in 2d, given the information attached to my first post. However that is as far as I can get. What I meant in the previous can be seen in the attachment. Link to comment Share on other sites More sharing options...
studiot Posted July 19, 2012 Share Posted July 19, 2012 (edited) [math]{V^\mu } = {V_\upsilon }[/math] Well that wasn't what you said in the first post, which was why I asked about your notation. Are you talking about contravarient and covarient or column vectors and row vectors? To premultiply by the square matrix you need a column vector. Edited July 19, 2012 by studiot Link to comment Share on other sites More sharing options...
UrgentAndrey Posted July 19, 2012 Author Share Posted July 19, 2012 (edited) Sorry thought I wrote that Yes I think so (contravarient and covarient) , all I have is the information I've put so far. I'm unsure as to my next step? Edited July 19, 2012 by UrgentAndrey Link to comment Share on other sites More sharing options...
studiot Posted July 19, 2012 Share Posted July 19, 2012 Look here under the section marked Euclidean Plane. There is an example calculation of the type you are trying to perform. http://en.wikipedia.org/wiki/Covariance_and_contravariance_of_vectors Link to comment Share on other sites More sharing options...
UrgentAndrey Posted July 19, 2012 Author Share Posted July 19, 2012 So using the link you gave me, is this correct? V^mu . V_mu = 1 Link to comment Share on other sites More sharing options...
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