polynomials (1 Viewer)

[samuelclarke]

the roots of the equation z^2 - 6iz + 3=0 are 'a' and 'b'. Without solving this equation:

i) Prove that lal + lbl > (greater than or equal to) 6

don't know what to do. please explain

 

[deswa1]

I'll give you a hint. If a and b are the roots, then using sums of roots, a+b=-b/a=6i/1
But the modulus of 6i is 6. Now try and extend this- Using sums of roots isn't valid for moduli (i.e. |a|+|b| does not neccessarily equal |-b/a|) but use this underlying principle

 

[samuelclarke]

@ deswa1: I still can't get it. lmao i get everything you explained so far but i still don't know where to go from there. lol

 

[Nooblet94]

@ deswa1: I still can't get it. lmao i get everything you explained so far but i still don't know where to go from there. lol

Use the triangle inequality.