Use linear approximation, i.e. the tangent line, to approximate +/81.1 as follows: Let f(z) = 4/z. Find the equation of the tangent line to f(z) at z = 81, using the fact that fi@) = 1 2.z W Using this, we find our approximation for v/ 81.1 is NOTE: For this part, give your answer to at least 9 significant figures or use an expression to give the exact answer. At the point shown on the function above, which of the following is true? @f>0,f">0 Of>0,f"0 Ofl