An ellipse has a vertex at (14, –1). The focus of the ellipse nearest that vertex is located at (8, –1). If the center of the el
lipse is located at (–1, –1), what is the equation of the directrix on that side of the ellipse?
x =
x =
2 answers:
Refer to the diagram shown below.
The right vertex is at (14, -1), and the center is at (-1, -1).
Therefore the semi-major axis is
a = 14 - (-1) = 15
The right focus is at (8, -1).
Therefore
c = 8 - (-1) = 9.
The distance of the directrix from the center is
d = c²/a = 9²/15 = 81/15 = 27/5.
Therefore the equation for the left directrix is
x = -1 - 27/5 = -32/5
Answer: x = -27/5
The right vertex is at (14, -1), and the center is at (-1, -1).
Therefore the semi-major axis is
a = 14 - (-1) = 15
The right focus is at (8, -1).
Therefore
c = 8 - (-1) = 9.
The distance of the directrix from the center is
d = c²/a = 9²/15 = 81/15 = 27/5.
Therefore the equation for the left directrix is
x = -1 - 27/5 = -32/5
Answer: x = -27/5
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Answer: 90 visitors per hour
Explanation: "Per hour" means in 1 hour, so we can rewrite the given statement using fractions as <em>450 visitors/5 hours = __visitors/1 hour</em>.
To find out what goes in the bank, notice that we
have a 1 in the denominator of our second fraction.
So we want to find a fraction that is equivalent
to 450/5 that has a 1 in the denominator.
If we divide the numerator and denominator of 450/5 by 5,
we get the equivalent fraction 90/1 or <em>90 visitors/1 hour</em>.
So now we have <em>90 visitors/1 hour = __visitors/1 hour</em>.
So a 90 must go in the blank.
This means that the museum sees 90 visitors per hour.
