r_h)=0}$.

The field equations {#derivingFE}
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The conformal approach to describing and studying black holes and other spherical solutions in Einstein–Weyl gravity and fully general Quadratic Gravity, based on the new form of the metric , is very convenient. Due to (\[confrelation\]), it enables to evaluate easily the Ricci and Bach tensors, entering the field equations (\[fieldeqsEWmod\]), from the Ricci and Bach tensors of the much simpler Kundt seed metric ${{{\rm{d}}}s^2_{\hbox{\tiny Kundt}}}$. In particular, to derive the explicit form of the field equations, it is possible to proceed as follows:

1.  Calculate all components of the Ricci and Bach tensors $R_{ab}^{{\hbox{\tiny Kundt}}}$ and $B_{ab}^{{\hbox{\tiny Kundt}}}$ for the Kundt seed metric $g_{ab}^{{\hbox{\tiny Kundt}}}$. Since such a metric (\[Kundt seed xy\]) is simple, containing only one general metric function of one variable $\H(r)$, its key curvature tensors are also simple. Their explicit form is presented in Appendix A.

2.  Use the well-known geometric relations for the Ricci and Bach tensors of conformally related metrics $g_{ab}^{{\hbox{\tiny Kundt}}}$ and ${g_{ab}=\Omega^2 \,g_{ab}^{{\hbox{\tiny Kundt}}}}$. Thus it is straightforward to evaluate the curvature tensors $R_{ab}$ and $B_{ab}$ for spherically symmetric geometries, starting from their forms of the Kundt seed calculated in the first step. In particular, since 