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Let-z-1-and-z-2-be-two-roots-of-the-equation-z-2-az-b-0-z-being-complex-Further-assume-that-the-origin-z-1-and-z-2-form-an-equilateral-triangle-Then-




Question Number 25075 by Mr easy last updated on 03/Dec/17
Let z_1 and z_2  be two roots of the equation  z^2 +az+b=0, z being complex. Further  assume that the origin, z_1  and z_2  form  an equilateral triangle. Then,
Letz1andz2betworootsoftheequationz2+az+b=0,zbeingcomplex.Furtherassumethattheorigin,z1andz2formanequilateraltriangle.Then,
Answered by ajfour last updated on 03/Dec/17
z_2 =z_1 e^(±i(π/3))  and  z_1 z_2 =b  z_1 +z_2 =−a  ⇒  z_2 ^3 =−z_1 ^3   or   (z_1 +z_2 )[(z_1 +z_2 )^2 −3z_1 z_2 ]=0  ⇒   −a[a^2 −3b]=0  ⇒     a=0    or  a^2 =3b .
z2=z1e±iπ3andz1z2=bz1+z2=az23=z13or(z1+z2)[(z1+z2)23z1z2]=0a[a23b]=0a=0ora2=3b.

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