Distance from (-2,3) to (-1,1)

  • Thread starter Thread starter nukeman
  • Start date Start date
AI Thread Summary
The center of the circle defined by the equation x^2 + 2x + y^2 - 2y - 3 = 0 is correctly identified as (-1,1). The distance from the point (-2,3) to this center is calculated using the distance formula: √((-1+2)^2 + (1-3)^2). The calculation confirms the distance as √5. Additionally, the point (-2,3) is confirmed not to be on the circle.
nukeman
Messages
651
Reaction score
0

Homework Statement



Find the distance from the point (-2,3) to the centre of the circle x^2 + 2x + y^2 - 2y - 3 = 0


Homework Equations





The Attempt at a Solution



The circle, I calculated that the center point is (-1,1) is that correct?

Then, I just input it into the distance formula: √(-1+2)^2 + (1 - 3)^2

?
 
Physics news on Phys.org


nukeman said:

Homework Statement



Find the distance from the point (-2,3) to the centre of the circle x^2 + 2x + y^2 - 2y - 3 = 0

Homework Equations



The Attempt at a Solution



The circle, I calculated that the center point is (-1,1) is that correct?

Then, I just input it into the distance formula: √((-1+2)^2 + (1 - 3)^2 )

?
What's you question?

Is the point, (-2,3), on the circle? ... just asking?
 


nukeman said:

Homework Statement



Find the distance from the point (-2,3) to the centre of the circle x^2 + 2x + y^2 - 2y - 3 = 0


Homework Equations





The Attempt at a Solution



The circle, I calculated that the center point is (-1,1) is that correct?

Then, I just input it into the distance formula: √(-1+2)^2 + (1 - 3)^2

?
Yes, to both questions.
 
I picked up this problem from the Schaum's series book titled "College Mathematics" by Ayres/Schmidt. It is a solved problem in the book. But what surprised me was that the solution to this problem was given in one line without any explanation. I could, therefore, not understand how the given one-line solution was reached. The one-line solution in the book says: The equation is ##x \cos{\omega} +y \sin{\omega} - 5 = 0##, ##\omega## being the parameter. From my side, the only thing I could...
Essentially I just have this problem that I'm stuck on, on a sheet about complex numbers: Show that, for ##|r|<1,## $$1+r\cos(x)+r^2\cos(2x)+r^3\cos(3x)...=\frac{1-r\cos(x)}{1-2r\cos(x)+r^2}$$ My first thought was to express it as a geometric series, where the real part of the sum of the series would be the series you see above: $$1+re^{ix}+r^2e^{2ix}+r^3e^{3ix}...$$ The sum of this series is just: $$\frac{(re^{ix})^n-1}{re^{ix} - 1}$$ I'm having some trouble trying to figure out what to...
Back
Top