AP EAMCET202021 Sep 2020Morning ShiftMathematicsComplex NumberActual
If ((2+i) ) is a root of the equation (x^3-5 x^2+9 x-5=0 ), then the other roots are
Options
- A1 and ((2-i) )
- B-1 and ((3+i) )
- C0 and 1
- D-1 and ((-2+i) )
Correct answer
A. 1 and ((2-i) )
Step-by-step solution
It is given that (2+i ) is the root of the equation (x^3-5 x^2+9 x-5=0 ), so another non-real complex root will be (2-i ). Now, let the third root is ( ), so by product of roots, we have ((2+i)(2-i) =5 =1 ) Hence, option (a) is correct.