\overrightarrow{\mathbf{a}}=\hat{\mathbf{i}}+\hat{\mathbf{k}} এবং \overrightarrow{\mathbf{b}}=2 \hat{\mathbf{i}}+\hat{\mathbf{j}}-\hat{\mathbf{k}} হলে \overrightarrow{\mathbf{a}} \times \overrightarrow{\mathbf{b}}= কত?