The equation of an ellipse is given below.400(x+13)2+625(y+6)2=1What are the foci of this ellipse?Choose 1 answer:(A) (−13+15,−6) and (−13−15,−6)(B) (−13,−21) and (−13,9)(C) (−28,−6) and (2,−6)(D) (−13,−6+15) and (−13,−6−15)
Q. The equation of an ellipse is given below.400(x+13)2+625(y+6)2=1What are the foci of this ellipse?Choose 1 answer:(A) (−13+15,−6) and (−13−15,−6)(B) (−13,−21) and (−13,9)(C) (−28,−6) and (2,−6)(D) (−13,−6+15) and (−13,−6−15)
Ellipse Equation: The equation of an ellipse is given by:400(x+13)2+625(y+6)2=1To find the foci of the ellipse, we need to identify the major and minor axes. The denominators of the fractions represent the squares of the semi-major and semi-minor axes lengths. The larger denominator corresponds to the square of the semi-major axis length, and the smaller denominator corresponds to the square of the semi-minor axis length.
Identifying Axes: In the given equation, the denominator 625 is larger than 400, which means that the semi-major axis is along the y-axis. The length of the semi-major axis is the square root of 625, which is 25. The length of the semi-minor axis is the square root of 400, which is 20.
Calculating Semi-Major and Semi-Minor Axes: The foci of an ellipse are located along the major axis at a distance 'c' from the center, where 'c' is found using the equation c=a2−b2, where 'a' is the length of the semi-major axis and 'b' is the length of the semi-minor axis.
Finding 'c': We calculate 'c' using the lengths of the semi-major and semi-minor axes:c=252−202=625−400=225=15
Determining Center of the Ellipse: The center of the ellipse is at the point (−13,−6), as indicated by the terms (x+13) and (y+6) in the equation. Since the major axis is along the y-axis, the foci will be located at (−13,−6±c).
Calculating Foci: Substituting the value of c into the coordinates of the foci, we get:Foci: (−13,−6+15) and (−13,−6−15)Simplifying the coordinates, we get:Foci: (−13,9) and (−13,−21)
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