Given that 2-3i is a root to the equation z^3+pz^2+qz-13p=0, show that p=-2 and q=5.

Substitute 2-3i into equation using part i (2-3i)3=-46-9i.  -46-9i+p(-5-12i)+q(2-3i)-13p=0. -46-18p+2q-9i-12pi-3iq=0. Real: -46-18p+2q=0 and Imaginary: -9-12p-3q=0. p=-2, q=5

Answered by William N. Maths tutor

9698 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Why is the derivative of the exponential function itself?


Express the following in partial fractions: (x^2+4x+10)/(x+3)(x+4)(x+5)


Why do we get cos(x) when we differentiate sin(x)?


Solve the equation |3x +4a| = 5a where a is a positive constant.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2024

Terms & Conditions|Privacy Policy
Cookie Preferences