Table 4 Numerical results for Example  2 with \(\pmb{h=2^{-8}}\) and \(\pmb{\beta =\frac{2}{3}}\)

\(\Vert u-u_{h} \Vert \)

3.75e−02

1.10e−02

3.58e−03

1.44e−03

1.30

\(\vert\!\vert\!\vert p-p_{h}\vert\!\vert\!\vert \)

9.00e−03

3.20e−03

1.50e−03

7.42e−04

1.02

\(\vert\!\vert\!\vert q-q_{h}\vert\!\vert\!\vert \)

1.95e−03

9.49e−03

4.71e−03

2.35e−03

1.00