grandes-ecoles 2015 QII.B.2

grandes-ecoles · France · centrale-maths2__psi Groups Group Homomorphisms and Isomorphisms
Let $\lambda \in \mathbb{R}^*$ and $(x_0, y_0) \in \mathbb{R}^2$ be fixed. We define: $$\Omega_{x_0, y_0, \lambda} = \left\{ \lambda(x,y) + (x_0, y_0) \mid (x,y) \in \Omega \right\}$$ By which geometric transformation(s) is the set $\Omega_{x_0, y_0, \lambda}$ the image of $\Omega$? Justify that $\Omega_{x_0, y_0, \lambda}$ is an open set of $\mathbb{R}^2$.
Let $\lambda \in \mathbb{R}^*$ and $(x_0, y_0) \in \mathbb{R}^2$ be fixed. We define:
$$\Omega_{x_0, y_0, \lambda} = \left\{ \lambda(x,y) + (x_0, y_0) \mid (x,y) \in \Omega \right\}$$
By which geometric transformation(s) is the set $\Omega_{x_0, y_0, \lambda}$ the image of $\Omega$? Justify that $\Omega_{x_0, y_0, \lambda}$ is an open set of $\mathbb{R}^2$.