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1. I've e been asked to find the equation of the circle with centre c ( -3, 2 ) and radius 5. (X + 3)^2 + (Y - 2)^2 = 25. That was easy. I was then asked to find the coordinates where the circle cuts the Y axis, P(0, -2) Q (0, 6). I was then asked to find the gradients of the tangents to the circle at P and Q. P = 3/4 and Q = - 3/4 also simple. However, the last section, asked me to calculate the coordinates of the point of intersection, Point R of the tangents P and Q. I thought, find the equations of the tangents and then solve them simultaneously. I'll be honest. This bit it not easy. Can someone please help me with this? Iceman perhaps, Can you help? It's just, I've got the C1 next month and I'm struggling with this bit. Thanks. Domo
2. look at P first
so the equation of the radius goes through (-3,2) and (0,-2) so has the equation y=-3/4x-2
so the equation of the tangent is perpendicular to this and hence y=3/4x-2
do this also for Q
that is the tangent is y=-3/4x+6
then solve simultaneously

[you should get (0.5,2)]

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Updated: April 2, 2013
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