| Alec
Armstrong |
Are there any complex roots to the equation x3 -1? (I know that there are real roots at -1,0,+1.) For x4 I know that these are at -1,+1,-i and +1. I also believe for x2 -1 that there are no complex roots? (Only at -1 and +1.) Many thanks! |
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| David
Loeffler |
Alec, Do you know about the factor theorem? It implies that a polynomial of degree n can't have more than n roots (real or complex), so in each case you have given all the roots of the equation. David |
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| Alice
Thompson |
For x3 -1, -1 and 0 are not roots. The two complex roots are and . |
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| David
Loeffler |
Good point. Well spotted, Alice. I misread Alec's first equation as x3 - x instead of x3 - 1. David |