Let f(x) = 1 1-2 (a) Determine the slope of the line secant to f(r) between the points r = 4 and z = 4+h. Your answer should be simplified to a form equivalent to for some integers a, b, c.. a b+ch (b) Using your result from (a) and an appropriate limit, find the slope of the tangent to the function f(z) at x = 4.