Nguyễn Thị Loan
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Trong mặt phẳng tọa độ $Oxy$, cho phép quay tâm $O$ góc quay ${{45}^{0}}$ ${{Q}_{\left( O,{{45}^{0}} \right)}}$. Tìm ảnh của đường tròn $\left( C \right):\,{{\left( x-1 \right)}^{2}}+{{y}^{2}}=4$.
C. ${{\left( x-\dfrac{\sqrt{2}}{2} \right)}^{2}}+{{\left( y-\dfrac{\sqrt{2}}{2} \right)}^{2}}=4$
B. ${{\left( x+\dfrac{\sqrt{2}}{2} \right)}^{2}}+{{\left( y+\dfrac{\sqrt{2}}{2} \right)}^{2}}=4$.
C. ${{\left( x-\dfrac{\sqrt{2}}{2} \right)}^{2}}+{{\left( y+\dfrac{\sqrt{2}}{2} \right)}^{2}}=4$.
D. ${{x}^{2}}+{{y}^{2}}+\sqrt{2}x+\sqrt{2}y-2=0$.
C. ${{\left( x-\dfrac{\sqrt{2}}{2} \right)}^{2}}+{{\left( y-\dfrac{\sqrt{2}}{2} \right)}^{2}}=4$
B. ${{\left( x+\dfrac{\sqrt{2}}{2} \right)}^{2}}+{{\left( y+\dfrac{\sqrt{2}}{2} \right)}^{2}}=4$.
C. ${{\left( x-\dfrac{\sqrt{2}}{2} \right)}^{2}}+{{\left( y+\dfrac{\sqrt{2}}{2} \right)}^{2}}=4$.
D. ${{x}^{2}}+{{y}^{2}}+\sqrt{2}x+\sqrt{2}y-2=0$.