How can you find the coefficients of a monic quadratic when you know only one non-real root?

We know that non-real roots appear in complex conjugate pairs. Hence when we know one root, we know both of them. Then, as we can factorise a quadratic in it's linear factors, we know our quadratic is a constant times the product of x minus the roots. Lastly, as our quadratic is monic, we must have that this constant is 1. Then find the coefficients by expanding the brackets.

WV
Answered by Ward V. Maths tutor

4038 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

How can the cosine rule be derived?


(a) By using a suitable trigonometrical identity, solve the equation tan(2x-π/6)^2 =11-sec(2x-π/6)giving all values of x in radians to two decimal places in the interval 0<=x <=π .


The function f is defined for all real values of x as f(x) = c + 8x - x^2, where c is a constant. Given that the range of f is f(x) <= 19, find the value of c. Given instead that ff(2) = 8, find the possible values of c.


Solve the quadratic inequality: x^2 - 5x + 4 < 0


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences