Is rationalizing the denominator an option

  • Thread starter Thread starter Justabeginner
  • Start date Start date
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
2 replies · 1K views
Justabeginner
Messages
309
Reaction score
1

Homework Statement


Evaluate x-> 3 for (x^3-27)/(x-3) by as many methods as you can think of.


Homework Equations





The Attempt at a Solution


I could only think of one:

1) (x-3)(x^2+3x+9)/(x-3)= (x^2+3x+9)
3^2 + 3(3) + 9= 27

What other methods can I do? Is rationalizing the denominator an option, even if it is redundant? Thank you.
 
Physics news on Phys.org
Justabeginner said:

Homework Statement


Evaluate x-> 3 for (x^3-27)/(x-3) by as many methods as you can think of.


Homework Equations





The Attempt at a Solution


I could only think of one:

1) (x-3)(x^2+3x+9)/(x-3)= (x^2+3x+9)
3^2 + 3(3) + 9= 27

What other methods can I do? Is rationalizing the denominator an option, even if it is redundant? Thank you.

The denominators already rational. Do you know l'Hopital's rule?
 
Yes, I do! Why didn't I think of that? :-p Thank you very much.