Recent content by VladZH

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    I Geodesics under coordinate transformation

    So basically if solution did exist that would mean the metric is flat?
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    I Geodesics under coordinate transformation

    Thanks for reply I understand the idea that connection can be zero at one point but not in others. But how I can derive it from the equation I wrote? Since that transformation will turn metric components to diagonal in any point. I just want to find an error in my steps
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    I Geodesics under coordinate transformation

    That is what I meant. Given coordinates xi and metric components gij I find such cordinates x'i=f(x1,...,xn) so that having Jacobian J_j^i=\frac{\partial x_i}{\partial x'_j} I am getting new metric components J^T*g*J=g'= \begin{pmatrix} 1 & 0 \\ 0 & 1 \end{pmatrix} Than I solve geodesic...
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    I Geodesics under coordinate transformation

    So how coordinate transforamtion is different from the example in my first post? For coordinate transform of metric tensor we have J^T*g'*J=g where J is Jacobian matrix.
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    I Geodesics under coordinate transformation

    What is the difference? What are vector components then?
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    I Geodesics under coordinate transformation

    I cannot fully understand what you mean. If we want to know vector components x^i in another coordinate system we can use equation x'^j=B^j_i x^i And for components of metric tensor respectively g'_{ij}=A^l_iA^k_j g_{kl} where A = J and B = J^{-1}. Why it is not coordinate transformation if we...
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    I Geodesics under coordinate transformation

    So in this specific example can I say that g' is equivalent to euclidean metric? For coordinate transformation I can use A-1, right?
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    I Geodesics under coordinate transformation

    Thanks for reply! Yes, I mean "equation of the form y = ax + b" . The solution of geodesic equation in coordinate system with component of metric as identity matrix gives y = ax + b. So I can take any metric in the coordinate system where its components are identity matrix and solving...
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    I Geodesics under coordinate transformation

    I will start with an example. Consider components of metric tensor g' in a coordinate system $$ g'= \begin{pmatrix} xy & 1 \\ 1 & xy \\ \end{pmatrix} $$ We can find a transformation rule which brings g' to euclidean metric g=\begin{pmatrix} 1 & 0 \\ 0 & 1\\ \end{pmatrix}, namely...
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    I Find Trajectory from A to B: Approaches & Solutions

    This is problem for my video game I tried to solve a simpler problem when we don't have the body C. Let P(r, φ) is a point on the circle. Let s between A and P. Hence, the time for spacecraft from A to B equals Δt=s/v The time for body B to get P is Δt=Δφ/ω. We get d/v=Δφ/ω where φ=sω/v Now...
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    I Find Trajectory from A to B: Approaches & Solutions

    Hello Given: Point A Body B with angular velocity ω C body with radius r Spacecraft with constant velocity v. We neglect the gravity of the bodies B, C The problem: Find the shortest trajectory for spacecraft from A to B What approaches might be here? How might the solution be changed if...
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    B Proof of the identity A\(A\B)=B

    Thank you, guys. Seems like I confused with the formultaion
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    B Proof of the identity A\(A\B)=B

    I'm trying to proof an identity from Munkres' Topology A \ ( A \ B ) = B By definition A \ B = {x : x in A and x not in B} A \( A \ B) = A \ (A ∩ Bc) = A ∩ (A ∩ Bc)c = A ∩ (Ac ∪ B) = (A ∩ Ac) ∪ (A ∩ B) = ∅ ∪ (A ∩ B) = A ∩ B What did I miss?
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    I Proving Effects of Stress-Energy Tensor on Curvature

    Ok, I see my approach is wrong. What are the approches to show that change of mass affects the curvature and change of velocity does not? How can we use Einstein field equation here?
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    I Proving Effects of Stress-Energy Tensor on Curvature

    Sorry. I'm not talking about covariance
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