Friday

November 21, 2014

November 21, 2014

Posted by **Grace** on Friday, January 20, 2012 at 12:44am.

((x-2)/5)^2 + ((y-4)/3)^2 = 1

Find the focal radius

Find the eccentricity

Write the parametric equations for the ellipse

Transform into the form, Ax^2 + By^2 + Cx + Dy + E = 0

- Precalc -
**Reiny**, Friday, January 20, 2012 at 9:51amI don't know which author you use, but focal radius can be defined in more than one way

http://www.mathwords.com/f/focal_radius.htm

for yours,

a = 5, b = 3

your ellipse will be horizontal, and

b^2 + c^2 = a^2

9+c^2 = 25

c^2 = 16

c = 4

eccentricity = c/a = 4/5 = .8

parametric equations:

x-2 = 5coss t ---> x = 5cost + 2

y-4 = 3sin t ----> y = 3sint + 4

original:

(x-2)^2 /25 + (y-4)^2 / 9 = 1

multiply by 225

9(x-2)^2 + 25(y-4)^2 = 225

9(x^2 - 4x + 4) + 25(y^2 - 8y + 16) = 225

I am sure you can finish it.

**Answer this Question**

**Related Questions**

Precalculus - I don't even how to go about this.... Mars is in an elliptical ...

calculus - (a) Modifying the parametric equations of a unit circle, find ...

pre-calculus - the foci of an ellipse are (0,2) (0,-2) and the eccentricity is 1...

geometry - The area of an ellipse in the form (x*x/a*a)+(y*y)/(b*b)=1 is A=3.14*...

Trig - Find a parametric equation for the ellipse. Make sure that the graph of ...

Calculus - find the equation for an ellipse that satisfies the following ...

Math-Precalculus-Parametric Equations - Ellipses - The graph of the equation (x-...

math/Check! - a. An ellipse is formed by stretching the graph of x^2+ y^2=1 ...

Geometry - For an ellipse, one focus is (0,0), one vertex is (2,0), and the ...

Math - Find a parametric description for the ellipse having the focus F=(0,-4), ...