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For questions 1-8, use the ellipse defined by the following equation: (x-4)^2/36+(y+2)^2/16=1

1. what are the coordinates of the center
2. What is the length of the major axis.
3. What is the length of the minor axis.
4. What is the sum of the local radii
5. What are the coordinates of the foci.
6. What are the coordinates of the vertices.
7. Find the eccentricity of the ellipse.
PLEASE SHOW WORK.

1 Answer

6 votes

Answer:

Explanation:

The standard form of the ellipse equation is (x-h)²/a² +(y-k)²/b² =1

This equation is for a horizontal ellipse. (a) is always bigger than (b) in ellipses. Because (a²) is under the x, that's why this ellipse is horizontal.

Now, let's answer the questions:

1. The center coordinates are (h,k) which are (4,-2) by comparing the two equations.

2. length of the major axis = 2a , let's find (a)

if you compare the two equations, a²=36 , that means a=6

Then 2a=12

3. length of the minor axis = 2b , let's find (b)

if you compare the two equations, b²=16 , that means b=4

Then 2b=8

4. the sum of the local radii = length of the major axis = 12

5. to find the foci, we have to find the value of (c), we have to use the equation a²=b²+c²

plugin a² and b², 36=16+c² , solve it, c=√20 =2√5

Now, to find the coordinates of the foci, we have to add and subtract the (c) value from the x-coordinate of the center while the y-coordinate stays the same (because this ellipse is horizontal).

the coordinates of the foci are (4+2√5 , -2) and (4-2√5 , -2)

6. the vertices are the end points of the major and the minor axes. To find the vertices on the major axis, add the value of (a) to the x-coordinate of the center while the y-coordinate stays the same.

(4+6,-2) and (4-6,-2) , this leads to (10,-2) and (-2,-2)

To find the vertices on the minor axis, add the value of (b) to the y-coordinate of the center while the x-coordinate stays the same.

(4,-2+4) and (4,-2-4) , this leads to (4,2) and (4,-6)

7. eccentricity (e)=c/a =(2√5)/6 = (√5)/3

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