3. (10 points) Find all relative extrema and points of inflection. Determine where the function is increasing or decreasing, concave up or concave down. Sketch the graph of the function based on your results. f(x) = xe-z 4. (10 points) Find an equation of the tangent line to the graph of the function at the point (1,1). The function y = f(z) is given implicitly.