Why the roots of Eq. x^2 + a*x + b = 0

  • Thread starter Lucasss84
  • Start date
  • #1
2
0
Why the roots of Eq. x^2 + a*x + b = 0 and of Eq. x + a*Sqrt[x] + b = 0 are not identically? How can I expand the second Eq. in simple fractions: x + a*Sqrt[x] + b = ... ?
Thank you. Lucas
 

Answers and Replies

  • #2
166
0


Because they are different equations! In the second equation, you can substitute [itex]y=\sqrt{x}[/itex] and it becomes [itex]y^2+ay+b=0[/itex]. Now the solution to the second equation is the same as the solution of the first, but remember that the solution we've got for the second equation is [itex]y[/itex], not [itex]x[/itex]! To find [itex]x[/itex], you have to square the solution you've got, and the solutions are different.
 
  • #3
HallsofIvy
Science Advisor
Homework Helper
41,833
964


Now, what do you mean by "expand in simple fractions"?
 

Related Threads on Why the roots of Eq. x^2 + a*x + b = 0

Replies
2
Views
2K
Replies
2
Views
2K
  • Last Post
Replies
12
Views
1K
  • Last Post
Replies
19
Views
1K
Replies
6
Views
1K
Replies
42
Views
5K
Replies
1
Views
2K
  • Last Post
Replies
9
Views
25K
  • Last Post
Replies
7
Views
3K
Top