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Leslie said that a circle with equation (x - 2)2 + (y - 7)2 = 13 has a tangent line represented by "y - 5 = -3/2(x + 1)". Right or wrong?

 May 5, 2020
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(x -2)^2  + (y - 7)^2  =  13

 

The center  = ( 2, 7)

 

y =  (-3/2)(x + 1) + 5

 

This would  mean the the point  ( -1, 5)  is  on the circle  (which is true)  because  (-1-2)^2  + (5-7)^2  =

3^2 + 2^2   =   13

 

It  also means that the slope  of the  line  containing the center  and this point is

 

[ 7-5] / [ 2 - -1]  =  2/3

 

The  tangent line line at (-1.5)  would have  a slope of -3/2

 

Looks like Leslie is correct  !!!

 

cool cool cool

 May 5, 2020

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