SOLUTION: the directions say to put the following equation into graphing form... i dont know how to do the squared sign on a key board so 2x2 is two x squared 2x2 + 3y2 + 4x - 12y -4 = 0

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: the directions say to put the following equation into graphing form... i dont know how to do the squared sign on a key board so 2x2 is two x squared 2x2 + 3y2 + 4x - 12y -4 = 0      Log On


   



Question 292355: the directions say to put the following equation into graphing form...
i dont know how to do the squared sign on a key board so 2x2 is two x squared
2x2 + 3y2 + 4x - 12y -4 = 0
all i could figure out was that it was an ellipse... i think

Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
2x%5E2%2B3y%5E2%2B4x-12y-4=0

Rearrange

2x%5E2%2B4x%2B3y%5E2-12y=4

Factor out coefficients of squared letters:

2%28x%5E2%2B2x%29%2B3%28y%5E2-4y%29=4

Complete the square in the first parentheses by
adding red%28%22%2B1%22%29 inside the first parentheses
which actually amounts to adding 2 to the left side 
because there is a 2 in front of the parentheses, so
we must add a 2 to the right side:

2%28x%5E2%2B2x%2Bred%281%29%29%2B3%28y%5E2-4y%29=4%2Bred%282%29

Complete the square in the second parentheses by
adding red%28%22%2B4%22%29 inside the second parentheses
which actually amounts to adding 12 to the left side 
because there is a 3 in front of the parentheses, so
we must add a 12 to the right side:

2%28x%5E2%2B2x%2Bred%281%29%29%2B3%28y%5E2-4y%2Bred%284%29%29=4%2Bred%282%29%2Bred%2812%29

Factoring the parentheses as perfect squares:

2%28x%2B1%29%5E2%2B3%28y-2%29=18

Get a 1 on the right by dividing through by 18

%282%28x%2B1%29%5E2%29%2F18%2B%283%28y-2%29%5E2%29%2F18=18%2F18

%28x%2B1%29%5E2%2F9%2B%28y-2%29%5E2%2F6=1

Since the largest denominator is under the term in
x, the ellipse has a horizontal major axis.  So we
compare it to:

%28x-h%29%5E2%2Fa%5E2%2B%28y-k%29%5E2%2Fb%5E2=1

h=-1, k=2, 

a%5E2=9 so a=sqrt%289%29=3

b%5E2=6 so b-sqrt%286%29

Its center is at (h,k) = (-1,2)

Plot the center:


 
Draw the major axis a=3 units both right and left of the center.
Draw the minor axis b=sqrt%286%29=2.449489743 units up and down
from the center.


Connect them to show the major and minor axes
of the ellipse:
 

 
Sketch in the ellipse:
 


 
Edwin