Recent content by world line

Hello i studied Sadri Hassani az mathematical physics book. if i want to learn topology (( for general relativity )) what it the best book for introduction ?

As i know, theoretically if u want to to touch some thing in the back u should run at speed more than light.

Hello what is the meaning of covaraint derivative ? where the ordinary derivative of a function whit respect to a variable is zero, it means that function doesn't depend on that variable.but what about covaraint derivative ? for example the metric tensor may depends on coordinate but its...

Thank you

for example : http://up.iranblog.com/images/90cm6lacnzsoxcju1v9.png that it is different with the corresponding spherical component if we use the covaraint unit vector the problem will be solved ! and both solution will have unique result is it correct ?

Hello i know how to derive the components of acceleration in other coordinates like spherical start here : http://up.iranblog.com/images/0mbwuclckbu51bxt8jfa.jpg and at last we have : http://up.iranblog.com/images/geotowiaxdya2s6ewxk.jpg also , i know that acceleration is a contravariant...

Hello any body can find my mistake ?! TO find the component of a vector in other coordinate we can use the transformation matrix : http://up98.org/upload/server1/01/z/ff96m5hl2uahgjw3u2un.jpg but why this does nt work for acceleration vector ? i mean why i can't derive the component of...