题目如图,底边ABABAB长为222的等腰直角△OAB\triangle OAB△OAB的边OBOBOB在xxx轴上,将△OAB\triangle OAB△OAB绕原点OOO逆时针旋转45∘45^{\circ}45∘得到△OA1B1\triangle OA_{1}B_{1}△OA1B1,则点A1A_{1}A1的坐标为( )A.(1,−2)(1,-\sqrt{2})(1,−2)B.(1,−1)(1,-1)(1,−1)C.(2,−2)(\sqrt{2},-\sqrt{2})(2,−2)D.(2,−1)(\sqrt{2},-1)(2,−1)知识点:勾股定理章节:图形的性质 / 三角形