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Find all roots of a function

  • Thread starter Dustinsfl
  • Start date
  • #1
699
5
x^4 + 7x^2 + 6 =0

I know the answers are imaginary but I don't remember how to solve this equation.
 

Answers and Replies

  • #2
105
0
Let t=x^2 and solve for t. Then once you have t, you can easily find x.
 
  • #3
699
5
If I do that and solve for t, I obtain two real solutions when all 4 all imaginary.
 
  • #4
105
0
using quadratic formula:

[tex] x^2=\frac{-7\pm \sqrt{49-24}}{2}[/tex]
[tex] x^2=\{-6,-1\} [/tex]

both values of x^2 for negative, so all 4 values of x are imaginary. Check your working?
 

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