DETAILS Use the function f( x) = _ 2 , find the following. x - 3 (=) Use the limit definition of the derivative to find F '(x). F ( x ) = (b) Find the equation of the tangent line at x=4. 4 DETAILS The graph of the function H(x) is shown below. Use the graph to answer the following. Find the value(s) of * where the function does not have a derivative? (Enter your answers as a comma-separated list. If an answer does not exist, enter DNE.)