SOLUTION: Locate the center, foci, vertices, ends of latera recta, & draw the ellipse. also compute the eccentricity & find the equation of the directices. 2.x^2/36+y^2/16=1

Algebra ->  Customizable Word Problem Solvers  -> Geometry -> SOLUTION: Locate the center, foci, vertices, ends of latera recta, & draw the ellipse. also compute the eccentricity & find the equation of the directices. 2.x^2/36+y^2/16=1       Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 948467: Locate the center, foci, vertices, ends of latera recta, & draw the ellipse. also compute the eccentricity & find the equation of the directices.
2.x^2/36+y^2/16=1

Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
x%5E2%2F36%2By%5E2%2F16=1
STANDARD FORM:
%28x-h%29%5E2%2F%28a%5E2%29%2B%28y-k%29%5E2%2F%28b%5E2%29=1
CENTER: Center is at (h,k) in this case (0,0). Center is at origin.
FOCI: Focus is (f) from center f%5E2=a%5E2-b%5E2
f%5E2=36-16=20 Find square root of each side.
f=sqrt%2820%29
Foci are at (-sqrt%2820%29,0) and (sqrt%2820%29,0).
VERTICES: In this case at (+ or - a,0) and a=sqrt%2836%29=6
Vertices at (-6,0) and (6,0)

ENDPOINTS OF LATERA RECTA: The latera recta are perpendicular to the major axis at the foci, and have length: 2b%5E2%2Fa. Since half is above and half is below the axis, we need half the length or b%5E2%2Fa=16/6=8/3
For the focus at (-sqrt%2820%29),0), the endpoints of the latus rectum are (-sqrt%2820%29,%288%2F3%29) and (-sqrt%2820%29,-%288%2F3%29)
For the focus at (sqrt%2820%29,0), the endpoints of the latus rectum are (sqrt%2820%29,%288%2F3%29) and (sqrt%2820%29,-%288%2F3%29)
ECCENTRICITY: Eccentricity epsilon=f/a=sqrt%2820%29%2F6
EQUATIONS OF DIRECTRICES: directrix is a line perpendicular to the main axis
on opposite the vertex from the focus, and same distance as the focus from the vertex. The directrix is outside the ellipse. The is a+(a-f) from the center,
or in this case, the directrix to the right of the origin is x=6%2B%286-sqrt%2820%29%29=12-sqrt%2820%29 and to the left of the origin x=-(12-sqrt%2820%29).