# User lovelymath

 Member for: 2 years (since Sep 20, 2014) Type: Registered user Full name: Location: About:

## Activity by lovelymath

 Score: 1,860 points (ranked #55) Title: Level 2 User Questions: 86 (54 with best answer chosen) Answers: 1 Comments: 3

## Wall for lovelymath

Briefly, if f(x)=k, x^3-x^2-x=k+11/4, so if k=-11/4, we have 3 solutions x(x^2-x-1)=0, x=0, (1±√5)/2. Using calculus you can discover where the max and min of f(x) are and you can use these to work out the range of k. Graphically, the cubic has two "humps" and the range of k is determined by the vertical distance between them, because if you slide the x axis between the extrema it cuts the curve in 3 places, which are the solutions. Post the question fully and I'll look out for it. In the meantime I hope this helps.
Jul 23, 2016 by Rod
Thank you for posting on my wall, but I have to confess that your question is beyond my scope. I'm sure you will find a user who can help you if you post your question on the site. In the meantime, I will try to educate myself in this field and better understand your problem and the means of solving it. Good luck with your answer. Perhaps Jennifer can help.
Nov 22, 2015 by Rod
78,075 questions