## Thomas' Calculus 13th Edition

a) $z$ ; b) $x$; c) $y$
The distance between two points can be calculated as: $\sqrt{(x-x_0)^2+(y-y_0)^2+(z-z_0)^2}$ a) Distance from point $P(x,y,z)$ to the xy-plane $(x,y,0)$ : $\sqrt{(x-x)^2+(y-y)^2+(z-0)^2}=\sqrt{z^2}=z$ b) Distance from point $P(x,y,z)$ to the yz-plane $0x,y,z)$ is : $\sqrt{(x-0)^2+(y-y)^2+(z-z)^2}=\sqrt{x^2}=x$ c) Distance from point $P(x,y,z)$ to the zx-plane$(x,0,z)$ is: $\sqrt{(x-x)^2+(y-0)^2+(z-z)^2}=\sqrt{y^2}=y$