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We have polynomial expression: E=x^4+4 Calculate x1 + x2 + x3 + x4 x1, x2, x3,x4 are...

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thales | (Level 1) Honors

Posted March 30, 2009 at 11:37 PM via web

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We have polynomial expression: E=x^4+4

Calculate x1 + x2 + x3 + x4

x1, x2, x3,x4 are the roots of the equation x^4+4=0

 

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giorgiana1976 | College Teacher | (Level 3) Valedictorian

Posted March 31, 2009 at 6:33 AM (Answer #1)

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We could use Viete expressions. They make the link between coefficients and roots in a given equation.

For example, if the equation is :

a*x^4 + b*x^3 + c*x^2 + d*x + e=0

x1 + x2 + x3 + x4=-b/a

In our equation, the coefficient b for x^3 is = 0, so

x1 + x2 + x3 + x4 = 0/1

x1 + x2 + x3 + x4=0

 

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