TITLE: evaluate f(x,y,z) # !h3 Problem: Given > f := (x,y,z) -> x*sin(y)+y*cos(z); f := (x, y, z) -> x sin(y) + y cos(z) # Compute: > `f(0,0,0)` = f(0,0,0); f(0,0,0) = 0 > `f(1,Pi/2,Pi)` = f(1,Pi/2,Pi); f(1,Pi/2,Pi) = 1 - 1/2 Pi > `f(1,Pi,Pi/2)` = f(1,Pi,Pi/2); f(1,Pi,Pi/2) = 0 > `diff(f(x,x,x),x)` = diff(f(x,x,x),x); diff(f(x,x,x),x) = sin(x) + x cos(x) + cos(x) - x sin(x) > collect(%,{sin(x),cos(x)}); diff(f(x,x,x),x) = (1 - x) sin(x) + (x + 1) cos(x) > `diff(f(y,y,0),y)` = diff(f(y,y,0),y); diff(f(y,y,0),y) = sin(y) + y cos(y) + 1 >