In Exercises 1 to 20, solve each equation.

Spencer Kociba MATH 200-005 Lecture Notes Week 6 10/24/2016 Directional Derivatives ● Definition for Directional Derivatives ○ If f(x,y) is a function and u =< u ,u > is a unit vector, then the directonal 1 2 derivative of f in the direction of u at (x ,y ) is denoted D f(x ,y ) and is given o o u o o by D f(x ,y ) = d [f(x + u s, y + u s)]|s = 0 u o o ds o 1 o 2 ○ D f(x ,y ) = lim f(o +1 ho y2+u ho−o(x ,y ) u o o h→0 h ● Notes ○ fx(o ,yo) = Duf(xo,yo) u=<1,0> ○