Christian Rau
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 Dec8 comment Matrices for which $\mathbf{A}^{-1}=-\mathbf{A}$ @AlexanderThumm Of course, as simple as it can be, me stupid! But what about more general matrices? Dec8 asked Matrices for which $\mathbf{A}^{-1}=-\mathbf{A}$ Sep17 awarded Enthusiast Sep13 revised Jacobian matrix of the Rodrigues' formula (exponential map) added 24 characters in body Sep13 answered Optimizing Cholesky factorization for multiple sparse matrices with same nonzero pattern Sep13 answered Jacobian matrix of the Rodrigues' formula (exponential map) Sep7 awarded Autobiographer Sep4 revised Finding the intersection point of many lines in 3D (point closest to all lines) Ported to latex for a more math appropriate style Sep4 suggested approved edit on Finding the intersection point of many lines in 3D (point closest to all lines) Sep4 awarded Commentator Sep4 comment Finding the intersection point of many lines in 3D (point closest to all lines) +1 I tried to work on the distance equation and derive it, but I completely forgot about Lagrange identity. Perfectly simple now. Sep4 comment Finding the intersection point of many lines in 3D (point closest to all lines) Are you sure your computation of the distance is correct? The dot product computes the cos of the angle, whose sin we want, therefore we need the cross product (or rather it's norm) instead of the dot product. Sep3 comment Why composite transformations are multiplied to the right side? @xEnOn Just to clarify, your example was badly-chosen, as OpenGL uses column vectors. But maybe you know this yourself and it was just a thought experiment. Sep2 answered Orthogonal matrix over cross product Sep1 comment How to calculate the x/y coordinate of F in this diagram (geometry) @Emperorlou If it helped in some way up-voting is appreciated (or maybe even accepting, as it's exactly the solution you came up with, in a format more appropriate to math.stackexchange). Sep1 revised How to calculate the x/y coordinate of F in this diagram (geometry) edited body Sep1 comment How to calculate the x/y coordinate of F in this diagram (geometry) This formula is not more exact than mine, it is exactly mine, transformed from vector algebra into programming (guess how dot and $\cdot$ and len2 and $\|\cdot\|^2$ are related to each other?). But I have to admit I had a little error in my solution so you might not have seen the similarity at first (corrected it already). Even if you searched for a programming solution, it is not really hard to transform vector algebra into programming, especially when you already have functions for the dot product and the vector norm and as we're on math.se, your answer is not really neccessary. Aug31 revised How to calculate the x/y coordinate of F in this diagram (geometry) edited body Aug31 answered How to calculate the x/y coordinate of F in this diagram (geometry) Aug29 revised Quaternion for an object that to point in a direction deleted 265 characters in body