h

τ

L2-error

order

1 2

1 2 4

0.00252081

-

1 2 2

1 2 8

0.0001626

3.9545

1 2 3

1 2 12

1.02427e-05

3.9887

1 2 4

1 2 16

6.41423e-07

3.9972

1 2 5

1 2 20

4.01086e-08

3.9993