Recent content by ParisSpart

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    Differential geometry Frenet

    with γ(s)=t'(s) and by scalar multiplying i found a2(s)=-1/k(s) a2'(s)=k'(s)/k^2(s) and (k'(s)/k^2(s))-a3(s)τ(s)=0 where a3(s)=k'(s)/k^2(s)*τ(s) and i concluded to this that we wanted
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    Differential geometry Frenet

    i have this γ'(s)=-a2(s)k(s)t(s)+a2(s)τ(s)b(s)+a2'(s)n(s)+a3'(s)b(s)-a3(s)τ(s)n(s) we don't know γ'(s) i think that its difficult to find a2(s) and a3 .
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    Differential geometry Frenet

    i replaced the n'(s) and b'(s) but why we must multiply with a suitable vector , for what reason? i am a little confused
  4. P

    Differential geometry Frenet

    if i differentiate i find this γ'(s)=a2(s)n'(s)+a2'(s)n(s)+a3'(s)b(s)+a3(s)b'(s) beacuse γ'(s)=t(s) i will replace this in this equation? and after that i am trying to replace the followings: b(s)=t(s)xn(s) , n(s)=t'(s)/k(s), t'(s)=k(s)n(s), n'(s)=-k(s)t(s)+τ(s)b(s), b'(s)=-τ(s)n(s) ?
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    Differential geometry Frenet

    no... can you tell me why? i focused on this that i said prior
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    Differential geometry Frenet

    but if we don't have γ'(s)=0 if we differentiate the γ(s)=a1(s)t(s)+a2(s)n(s)+a3(s)b(s) with what γ'(s) will be equal?
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    Differential geometry Frenet

    i think that a1(s)=0 because i supposed that for γ'(s)=0 we know that t(s)=γ'(s) and then t(s)=0 and a1(s)=0
  8. P

    Differential geometry Frenet

    because γ(s)*γ(s)=c where c is a constant and then 2γ(s)γ'(s)=0
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    Differential geometry Frenet

    i tried to the derivative and i found this : γ'(s)=a2(s)n'(s)+a2'(s)n(s)+a3'(s)b(s)+a3(s)b'(s) , we know that γ'(s)=0 beacuse we are on the surface of sphere , after that i tried to replace n'(s)=-k(s)t(s)+τ(s)b(s) and the other types?
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    Differential geometry Frenet

    a1(s) will be zero? and after that with differentiation i will conclude to the the expression i wrote?
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    Differential geometry Frenet

    i think that if i find a way to combine γ with the types of frenet and derivative them i will find the problem
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    Differential geometry Frenet

    my problem is:even γ: I-> R ^3 curve parameterized as to arc length (single speed) with curvature k (s)> 0 and torsion τ(s)>0. we assume that the γ is at the surface sphere with center the origin. Show that for any s we have: γ(s)=-(1/k(s))*n(s) + (k'(s)/(k^2(s)*τ(s)))*b(s) and he gives us a...
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    Differential geometry Frenet

    even γ: I-> R ^ 2 curve parameterized as to arc length (single speed) with curvature k (s)> 0 and torsion τ(s)> 0. I want to write the γ(s) as a combination of n(s), t(s), b(s). these are the types of Frenet. the only thing i know is that the types of Frenet are t(s)=γ'(s) ...
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    Exploring Tangent Planes and Vertical Curvature in Differential Geometry

    Consider the surface S defined as the graph of a function z = 2x ^ 2 - y ^ 2 i) find a basis of the tangent plane Tp surface S at the point p = (-1,2, -2) ii) find a non-zero vector w in Tp with the property that the vertical curvature at point p in the direction of vector w is zero for...
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    Is t(s) perpendicular to the radius of the surface sphere at point γ(s)?

    and because t(s)=γ'(s) and γ(s) ιs radious t(s) is perpendicular on γ(s)?
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