plot tangent to a contour

Hello everyone

In Paraview 5.8.0, I plot 1 contour line (an arc) of the density field (thick black colored line) on top of the density isocolor field (blue to red color variation). See below :


Can someone suggest me a good way to plot a tangent to this arc-shaped contour line at a specific point? This is because, I would like to estimate the angle made by the tangent at that point with the horizontal direction (x-axis in this case).