Differentials ?Consider the following functions and express the relationship between a small change in x and the corresponding change in y in the?form dy = ? ? ? f(? )? x. ? ? f(? )= ln(1 ? x ? )

Solution 38E STEP 1 Let f be the function differentiable on an interval containingx.The small change in x is denoted by the differential dx. The corresponding change in f is approximated by the differential dy = f(x)dx STEP 2 Given the function f(x) = ln(1x) Then f (x) = 1 = 1 1x x1 Therefore dy = f (x)dx dy = 1 dx x1