2. Use implicit differentiation to find xz / and yz / for 2 ln zyxyz =+ 3. Use the first principles to find ),( yxfx and ),( yxf y if yxxyyxf 22 ),( = 4. Find the differential of the function 22 zy xzev = 5. Use the Chain Rule to find sz / and tz / if ( )( ) ln)12sin( += rz , t s r = , 22 ts = 6. Use a tree diagram to write out the Chain Rule (assume all functions are differentiable) for ),,( tsrfw = where ),( yxrr = , ),( yxss = , and ),( yxtt = 7. Show that the given function ),,( zyxu satisfies the 3-dimensional Laplace's partial differential equation 02 2 2 2 2 2 = + + z u y u x u where: 222 1 zyx u ++ = 8. The length L, width W, and height H of a box change with time. As a certain instant the dimensions are L = 1m and W = H = 2m, and L and W are increasing at a rate of 2 m/s while H