SOLUTION: Solve: X^4 + 100 = 0 The problem is that the students only have factoring, irrational, and complex numbers as their background. Let a = x^2 a^2 = -50 a = 5i*{sqrt(2)}

Algebra ->  Exponents -> SOLUTION: Solve: X^4 + 100 = 0 The problem is that the students only have factoring, irrational, and complex numbers as their background. Let a = x^2 a^2 = -50 a = 5i*{sqrt(2)}       Log On


   



Question 663690: Solve:
X^4 + 100 = 0
The problem is that the students only have factoring, irrational, and complex numbers as their background.
Let a = x^2
a^2 = -50
a = 5i*{sqrt(2)}
x^2 = 5i*{sqrt(2)}
How to find x?
Use synthetic division and guess? That doesn't seem to work too well either?
Recommendations for new Algebra II students? Thanks.

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Solve:
X^4 + 100 = 0
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x%5E4+=+-100
Use DeMoivre's Theorem
x^4 = 100cis(180) + n*360
x = sqrt(10)cis(45) + n*90
x = sqrt(10)cis(45), ...cis(135), cis(225), cis(315)
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Probably more than Algebra 2 can do, tho.
--> not an appropriate problem for Algebra 2.