# Sup

 May 1 comment Is there a fundamental misunderstanding here or have I made an algebraic slip?@JasonDeVito : Also it is now ${\dot{u}^2\over 1-u^2}=1$ not simply $\dot{u}=1$ May 1 comment Is there a fundamental misunderstanding here or have I made an algebraic slip?@JasonDeVito : No probs, note that in the original coordinates, that curve is just $a=u, b=0$. ${d\over dt} ({1\over 1-u^2}\dot{u})={1\over 2}({\partial \over \partial u}({1\over 1-u^2})\dot{u}^2)$ May 1 awarded Teacher May 1 comment Is there a fundamental misunderstanding here or have I made an algebraic slip?Ok, apparently I cannot accept the answer within 2 days... Apr 30 comment Is there a fundamental misunderstanding here or have I made an algebraic slip?@JasonDeVito: I have added an answer, as per requested. Apr 30 answered Is there a fundamental misunderstanding here or have I made an algebraic slip? Apr 30 comment Is there a fundamental misunderstanding here or have I made an algebraic slip?@FernandoMartin: But I have to wait a further 3 hours since it says that I have too few "reputation points" so I can't post an answer within 8 hours of my asking the question... Apr 30 revised Is there a fundamental misunderstanding here or have I made an algebraic slip?added 285 characters in body Apr 30 revised Is there a fundamental misunderstanding here or have I made an algebraic slip?added 3 characters in body Apr 30 revised Is there a fundamental misunderstanding here or have I made an algebraic slip?added 392 characters in body Apr 30 comment Is there a fundamental misunderstanding here or have I made an algebraic slip?@JasonDeVito: thanks for commenting! en.wikipedia.org/wiki/… offers a bit of info. But generally, for a Riemannian metric of the form $Edu^2+2Fdudv+Gdv^2$ and a geodesic $g(t)=(a(t),b(t))$, the Euler Lagrange equations are ${d\over dt} (E\dot{a}+F\dot{b})={1\over 2} (E_u\dot{a}^2+2F_u\dot{a}\dot{b}+G_u\dot{b}^2)$ and ${d\over dt} (F\dot{a}+G\dot{b})={1\over 2} (E_v\dot{a}^2+2F_v\dot{a}\dot{b}+G_v\dot{b}^2)$ Apr 30 comment Is there a fundamental misunderstanding here or have I made an algebraic slip?Anyone, please? Apr 30 awarded Editor Apr 30 revised Is there a fundamental misunderstanding here or have I made an algebraic slip?added 16 characters in body Apr 30 awarded Student Apr 30 asked Is there a fundamental misunderstanding here or have I made an algebraic slip?