what does it mean if "b^2 - 4ac < 0" for a quadratic equation (eg y = a*x^2 + b*x + c)

The question comes from the quadratic equation r = (-b +- sqrt(b2 - 4ac)/2a where r is the root or x coordinate where the line crosses the x-axsis (the y coordinate is always 0). If b2 - 4ac < 0 then to find the root you whoud have to take the sqrt of a negative number which doesnt exsist (at least it doesn't for standard maths alevel students) and so the line doesnt have any roots. This means that it doesnt cross the x-axsis.

NW
Answered by Nick W. Maths tutor

4621 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

How to differentiate y=2x(x-2)^5 to find dy/dx?


Calculate the distance of the centre of mass from AB and ALIH of the uniform lamina.


The line AB has equation 5x + 3y + 3 = 0. The point with coordinates (2k + 3, 4 -3k) lies on the line AB. How do you find the value of k.


Demonstrate that (2^n)-1 is not a perfect square for any n>2, n ∈ N.


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