Question #30429

2 Answers
May 9, 2017

The standard form is (x+1)^2/(sqrt5)^2+(y-1)^2/4^2=1

Explanation:

Let's rearrange the equation by completing the squares

16x^2+5y^2+32x-10y-59=0

16(x^2+2x)+5(y^2-2y)=59

16(x^2+2x+1)+5(y^2-2y+1)=59+16+5

16(x+1)^2+5(y-1)^2=80

16(x+1)^2/80+5(y-1)^2/80=1

(x+1)^2/5+(y-1)^2/16=1

(x+1)^2/(sqrt5)^2+(y-1)^2/4^2=1

This is an ellipse, center =(-1,1)

graph{(16x^2+32x+5y^2-10y-59)((x+1)^2+(y-1)^2-0.01)=0 [-11.25, 11.25, -5.625, 5.625]}

May 9, 2017

Yes

Explanation:

To convert the equation to standard form for ellipses, we need to complete the square.
Note that the standard form for an ellipse is:
((x-h)^2)/a^2+((y-k)^2)/b^2=1 with a horizontal semi-major axis
or
((x-h)^2)/b^2+((y-k)^2)/a^2=1 with a vertical semi-major axis
where (h,k) is the center of the ellipse and a>b, where a is the length of the semi-major axis and b is the length of the semi-minor axis

Given the starting equation 16x^2+5y^2+32x-10y-59=0, we first add 59 to both sides to isolate the variables and the constants:
16x^2+5y^2+32x-10y=59

Now we can complete the square for x and y:
16(x^2+2x)+5(y^2-2y)=59
16(x+1)^2-16+5(y-1)^2-5=59
16(x+1)^2+5(y-1)^2=80

Now we divide both sides by 80 to make the right-hand side equal to 1 for standard conic form:
((x+1)^2)/5+((y-1)^2)/16=1

Therefore, this conic is a vertical ellipse centered at (-1,1) with a semi-major axis of length 4 and a semi-minor axis of length sqrt(5).