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

WN
Answered by William N. Maths tutor

10371 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Differentiate the equation y = (1+x^2)^3 with respect to (w.r.t.) x using the chain rule. (Find dy/dx)


Find the shortest distance between the line L: x=1+t, y=1+2t, z=1-t and the point A: (2,3,4)


An open-topped fish tank is to be made for an aquarium. It will have a square base, rectangular sides, and a volume of 60 m3. The base materials cost £15 per m2 and the sides £8 per m2. What should the height be to minimise costs?


How do you find the gradient of a parametric equation at a certain point?


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 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences