If the initial guess value is close to a root, this algorithm will converge rapidly to the solution. However, it is quite sensitive to the initial guess value. Figure 4-18b shows the result of a slight change in the initial guess from Xl = 1.8to Xl =2.5. With this slightly different guess it converges to another root. Note also that if we choose an initial guess of Xl = 3.579 which corresponds to a local maximum of this function, the tangent line will be horizontal and will not intersect the X axis at all. The method fails in this situation. Can you suggest a value of Xl that would cause it to converge to the root at X = 6.74?