iterative methods: spider/cobweb diagrams - please help!!!

I am working on iterative methods:

The question is:

a) Starting with x0 = 1 use the iterative formula

x n+1 = 1 / (xn + 4)

to find x1, x2, x3 and x4.

b) Illustrate the convergence on a spider or cobweb diagram.

I can do part a fine, and I get it right. Fir part b, I know you have to draw the graph, and also draw the line y = x. Then show the convergence at the point of intersection. But i don't know how exactly the spider/cobweb diagram is drawn. I know its a lot to ask, but could anyone possible show me how it would be drawn in this case?

I'll rep anyone who does, and be forever grateful to them!!!!

Many thanks in advance. :smile:

Reply 1

barry_4_england

Start from x0=1 and go up the the curve and then across to the line y=x, so that your y value from x0 is now your new x value (x1). And just keep doing this and it will either be a cobweb or a staircasey thinger.