1.df/dx=2xy^3
df/dy=3x^2y2
df/dz=4z^3
dx/ds=2s
dy/ds=t^2
dz/ds=2st
df/ds=7s^6t^6+8s^7t^4
3.df/ds=6rs^2
df/dr=2s^3+4r^3
5.dg/du=-10sin(10u-20v)
dg/dv=20sin(10u-20v)
7.dF/dy=xe^(x^2+xy)
15.dg/du=2cos(2)
17.26.8ft/s
23.F_x=x^2+y
F_y=2yz+x
F_z=2xz+y^2
dz/dy=2y+x/(2xz+y^2)
dz/dx==z^2+y/(2xz+y^2)
27.dz/dx=-(2xy+z^2)/(2xz+y^2)
29.dx/dy=-xe^(xy)+1/(xcos(xz))
31.dw/dy at(1,1,1)
=-(1)(1+1)^2/(1(4)+4)
=-1/2


1.Saddle pt - (0,0)
loc mins - (2sqrt(2),sqrt(2)),
(-2sqrt(2),sqrt(2))
abs min - (-4)
3.saddle pt - (0,0)
local min - (13/64,-13/32),
(-1/4,1/2)
5.saddle pts - (0,0),(0,-1),(1,0)
loc min - (1/3,-1/3)
7.loc min (-2/3,1/3)
11.saddle pt (0,+-sqrt(2))
loc min (-1,1) 
loc max (2/3,0)
13.saddle pt (0,0)
loc min - (+-1, +-1)
19.loc max - (1,.5)
21.saddle pt - (2/3,-.5)
23.loc min - (-1/6, -17/18)
29.glob max - 2
glob min - none
35.max - 1/3