Can someone help me with this exercise in DrRacket?

[JohanVenegas]

[spdegabrielle]

How to ask for help

Here's a checklist to make things easier when asking for help, in order:

1. What is the task?
2. How far have you come? (Provide the smallest working example of your problem if you can)
3. What exactly are you struggling with?
4. What approaches have you tried to solve it?

[soegaard]

Lookup Newton iteration in SICP.