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    How would you answer these two:

    1.) AB is a chord of a circle where A is at (1,3) and B is at (4,4). The tangent to the circle at A is the line y=2x + 1.
    Find the equation of the circle.

    and 2.) Line y=-2 is a tangent to the circle x^2 + y^2 + 2x - 4y = 11.
    Find the co-ordinates of the point of contact.
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    1) Tangent at A is perpendicular to the radius (so what is the line of equation which is includes the radius?) and perpendicular bisector of the chord AB goes through the centre. How can you use that information to find the centre of the circle ?

    I have no idea whether this is the best way, probably others.

    2) Sub in y = -2 into the circle and find x.
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    (Original post by insparato)
    1) Tangent at A is perpendicular to the radius (so what is the line of equation which is includes the radius?) and perpendicular bisector of the chord AB goes through the centre. How can you use that information to find the centre of the circle ?

    I have no idea whether this is the best way, probably others.

    2) Sub in y = -2 into the circle and find x.
    I would do A that way and form a triangle to work out radius/centre.
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    I got it in the end but thanks you were helpful
 
 
 
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