Real-valued function of two or more variables
#[Function of three variables][Función de tres variables]#
A
real-valued function $f$ of three variables is a rule for manufacturing a new number, called $f(x,y,z)$ (and read '$f$ of $(x,y,z).$') from a triple of numbers $(x,y,z).$
#[Examples][Ejemplos]#
1. \t $f(x,y,z) = 3x+y-z$ \t
\\ \t $f(1,2,-1) = 3(1) + 2 - (-1) = 6 \qquad$ \t
\\ \t $f(2,0,6) = 3(2) + 0 - 6 = 0$ \t
\\
\\ 2. \t $f(x,y,z) = x^2+y^2+ z^2$ \t
\\ \t $f(4,-1,1) = 4^2+(-1)^2+1^1 = 18 \quad$ \t
\\ \t $f(0,0,0) = 0^2+0^2+0^2 = 0$ $\quad$ \t