Just wondering how to control the variable X using a radio button (bar) in Manipulate because it appears to not be working. If anyone could help, that would be great! Manipulate[ {evals, evecs} = Eigensystem[( { {-\[Sigma], \[Sigma], 0}, {r – X[[3]], -1, -X[[1]]}, {X[[2]], X[[1]], -\[Beta]} } )]; GraphicsColumn[{Show[VectorPlot3D[( { {-\[Sigma], \[Sigma], 0}, {rRead more