Figure 1

Graphs of the approximations ${\mathit{\alpha }}_{{\mathit{n}}_{\mathbf{1}}}$ , ${\mathit{\beta }}_{{\mathit{n}}_{\mathbf{1}}}$ (in violet), ${\mathit{\alpha }}_{{\mathit{n}}_{\mathbf{2}}}$ , ${\mathit{\beta }}_{{\mathit{n}}_{\mathbf{2}}}$ (in green) and ${\mathit{\alpha }}_{{\mathit{n}}_{\mathbf{3}}}$ , ${\mathit{\beta }}_{{\mathit{n}}_{\mathbf{3}}}$ (in blue), with ${\mathit{\alpha }}_{{\mathit{n}}_{\mathit{k}}}$ , ${\mathit{\beta }}_{{\mathit{n}}_{\mathit{k}}}$ , defined by ( 41 ), ( 42 ) with $\mathit{L}\mathbf{=}{\mathit{L}}_{\mathbf{0}}$ , such that ${\mathbf{\parallel }{\mathit{\beta }}_{{\mathit{n}}_{\mathit{k}}}\mathbf{-}{\mathit{\alpha }}_{{\mathit{n}}_{\mathit{k}}}\mathbf{\parallel }}_{\mathbf{\infty }}\mathbf{<}{\mathbf{10}}^{\mathbf{-}\mathit{k}}$ for $\mathit{k}\mathbf{\in }\mathbf{\{}\mathbf{1}\mathbf{,}\mathbf{2}\mathbf{,}\mathbf{3}\mathbf{\}}$ .