A comet follows a hyperbolic path in which the sun is located at one of its foci. The path of the comet can be modeled by the hyperbola shown below, centered at the origin and opening left/right. If the closest distance the comet reaches to the sun is 152 million km, and the sun is 380 million km from the center of the hyperbola, write an equation of the hyperbola (in millions of km).

152

380

5 answers

We can use the standard form of the equation of a hyperbola centered at the origin with vertices on the x-axis:

(x^2/a^2) - (y^2/b^2) = 1

where a is the distance from the center to each vertex, and b is the distance from the center to each foci. Since the hyperbola opens left/right, we know that a > b.

We are given that the distance from the sun (one of the foci) to the center is 380 million km, so b = 380. We are also given that the closest distance the comet reaches to the sun (one of the foci) is 152 million km. Since the hyperbola is centered at the origin, this distance is also equal to the absolute value of the x-coordinate of one of the points on the hyperbola. Let's call this distance x. Then, using the distance formula:

sqrt(x^2 + y^2) = 152

Squaring both sides and simplifying, we get:

x^2 + y^2 = 23104

Now we can substitute this expression for x^2 in the standard form equation of the hyperbola:

(x^2/a^2) - (y^2/380^2) = 1

(23104/a^2) - (y^2/380^2) = 1

Multiplying both sides by a^2:

23104 - (y^2/380^2) * a^2 = a^2

Rearranging:

(y^2/380^2) * a^2 + a^2 = 23104

Factoring out a^2:

a^2 * (y^2/380^2 + 1) = 23104

Dividing both sides by (y^2/380^2 + 1):

a^2 = 23104/(y^2/380^2 + 1)

This gives us a formula for a in terms of y. We can use the fact that a > b to eliminate the possibility of a negative value of a, which would correspond to the hyperbola opening up/down rather than left/right. This gives us the inequality:

a > b

sqrt(23104/(y^2/380^2 + 1)) > 380

Simplifying, and noting that y and a are both positive:

23104/(y^2/380^2 + 1) > 144400

y^2/380^2 + 1 < 23104/144400

y^2/380^2 < 0.936

y^2 < 0.936 * 380^2

y^2 < 134758.4

Therefore, the equation of the hyperbola is:

(x^2/a^2) - (y^2/380^2) = 1

where a satisfies:

a > 380 and a^2 = 23104/(y^2/380^2 + 1)

and y satisfies:

-y^2 < -134758.4

Note that there are two branches of the hyperbola, corresponding to positive and negative values of x. We could write equations for each branch separately, but the above formula for a and the inequality for y apply to both branches.
your answer is wrong
I apologize for any confusion caused. Please let me know where there was an error in my solution so that I can correct it.
Using the numbers they gave, we have
c-a = 152
c = 380
That means that
a = 228
b = 304
And the equation is
x^2/228^2 - y^2/304^2 = 1
or
x^2/51984 - y^2/92416 = 1
Thank you for pointing out the mistake in my solution. I appreciate it and apologize again for any confusion caused. Your solution is correct and agrees with the given information.