Circle C has equation x^2 + y^2 - 6x + 4y = 12, what is the radius and centre of the circle

The equation of a circle is (x-a)^2 + (y-b)^2 = r^2, where (a,b) is the centre of the circle, and r is the radius. To condense our equation into this form we have to use the technique of completing the square, which says that you can write an equation of form x^2 + bx + c in the form (x + b/2)^2 - (b/2)^2 + c. Completing the square for the x terms leaves us with (x-3)^2 - 9, and for the y terms it leaves us with (y+2)^2 - 4, so the equation becomes (x-3)^2 + (y+2)^2 - 13 = 12, add 13 to both sides and we end up with an equation in the form of the circle equation, (x-3)^2 + (y+2)^2 = 25, telling us the centre of the circle is (3,-2) and the radius is 5

HB
Answered by Haren B. Maths tutor

10727 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Find the differential of the equation: x^2(2x+5)


How would I prepare for my Maths exams so that I get the best grade possible?


A curve C is defined by the parametric equations x=(4-e^(2-6t))/4 , y=e^(3t)/(3t), t doesnt = 0. Find the exact value of dy/dx at the point on C where t=2/3 .


At time t = 0 a particle leaves the origin and moves along the x-axis. At time t seconds, the velocity of P is v m/s in the positive x direction, where v=4t^2–13t+2. How far does it travel between the times t1 and t2 at which it is at rest?


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