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+--- Thread: A level maths: coordinate geometry of circles? (/thread-122684.html)
A level maths: coordinate geometry of circles? - Hello - 03-28-2014 12:48 PM
I am revising coordinate geometry for my maths mock this week.
I worked out a question on the line that intersects the circle. I got the coordinates to be 9,-2 and 1,2 but it says in the answers this is wrong. Can someone explain to me what i did wrong? This is my working https://twitter.com/hellojessiej/status/427426204929765376 (i uploaded it to an old twitter account i made years ago). On the photo i wrote the question too. Can you explain where i have gone wrong please, and how i'd do it right?
- Amy - 03-28-2014 12:58 PM
4x5x0 = 0
But you don't go on to actually use the quadratic formula, so this mistake becomes irrelevant.
y^2 - 4y does not equal (y+2)(y-2). That would be y^2 - 4.