Tangent Lines of Two Circles Intersect At Point

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SUMMARY

The discussion focuses on finding the points where the tangent lines of two circles intersect at the point (11/3, 2/3). The equations of the circles are given as Circle 1: x² + (y-3)² = 5 and Circle 2: (x-2)² + (y+3)² = 2. The derivatives of each circle are calculated as y'(x) = -(x)/(y-3) for Circle 1 and y'(x) = (2-x)/(y+5) for Circle 2. The solution involves using the slope-intercept equation to derive the tangent lines and finding their intersection points with the respective circles.

PREREQUISITES
  • Understanding of implicit differentiation in calculus
  • Familiarity with the slope-intercept form of a line
  • Knowledge of circle equations in Cartesian coordinates
  • Ability to solve systems of equations
NEXT STEPS
  • Learn how to apply implicit differentiation to find slopes of curves
  • Study the slope-intercept form of a line and its applications in geometry
  • Explore methods for finding intersection points of curves
  • Investigate the properties of tangent lines to circles
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Students studying calculus, particularly those focusing on geometry and the properties of circles, as well as educators looking for examples of tangent line problems.

VectorCereal
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Homework Statement



The tangent lines of two circles intersect at point (11/3,2/3). What are the two points that each tangent line touches on its respective circle?

Homework Equations



Circle 1: x^2 + (y-3)^2 =5
Circle 2: (x-2)^2 + (y+3)^2 = 2

The Attempt at a Solution



I found the derivatives of each circle.

Circle 1: y'(x) = -(x)/(y-3)
Circle 2: y'(x) = (2-x)/(y+5)

Do I have to use the slope-intercept equation somehow? y-yo=m(x-xo)

I'm not quite sure what do to next... :S
 
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help anyone??
 
VectorCereal said:

Homework Statement



The tangent lines of two circles intersect at point (11/3,2/3). What are the two points that each tangent line touches on its respective circle?

Homework Equations



Circle 1: x^2 + (y-3)^2 =5
Circle 2: (x-2)^2 + (y+3)^2 = 2

The Attempt at a Solution



I found the derivatives of each circle.

Circle 1: y'(x) = -(x)/(y-3)
Circle 2: y'(x) = (2-x)/(y+5)

Do I have to use the slope-intercept equation somehow? y-yo=m(x-xo)

I'm not quite sure what do to next... :S
Hello VectorCereal. Welcome to PF !

Yes, using the slope intercept equation of a line can be helpful. In this case, (x0, y0) = (11/3, 2/3) .

Also, it looks to me like the problem can be solved for either circle independently of the other circle.

For Circle 1:

If you plug y'(x) = -(x)/(y-3) in for m in the slope intercept equation, you get the equation of another circle. See where this circle intersects with Circle 1.

Check your answer, because this seems like a weird method of solution !
 

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