db1d53…: “Aside from the frigid number”

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In $\R ^2$ the set of points satisfying $x=0$ is:

the $x$ -axis the $y$ -axis the $(x,y)$ -plane the $(y,z)$ -plane the $(x,z)$ -plane none of these

In $\R ^3$ the set of points satisfying $x=0$ is:

the $x$ -axis the $y$ -axis the $(x,y)$ -plane the $(y,z)$ -plane the $(x,z)$ -plane none of these