Find the equation of a parabola with focus (2, -3) and directrix x = 5.

The equation of the parabola is (y + 3)² = -6(x - 7/2)

Step-by-step explanation:

* Lets revise the equation of a parabola

- If the equation is in the form (y − k)² = 4p(x − h), then:

• Use the given equation to identify h and k for the vertex, (h , k)

• Use the value of k to determine the axis of symmetry, y = k

• Use h , k and p to find the coordinates of the focus, (h + p , k)

• Use h and p to find the equation of the directrix, x = h − p

* Now lets solve the problem

∵ The directrix ⇒ x = 5

∴ The form is (y − k)² = 4p(x − h)

∵ The directrix is x = h - p

∴ h - p = 5 ⇒ (1)

∵ The focus is (h + p , k)

∵ The focus is (2 , -3)

∴ k = -3

∴ h + p = 2 ⇒ (2)

- Add (1) and (2) to find h

∴ 2h = 7 ⇒ ÷ 2 for both sides

∴ h = 7/2

- Substitute this value in (1) or (2) to find p

∴ 7/2 + p = 2 ⇒ subtract 7/2 from both sides

∴ p = -3/2

* Now we can write the equation

∴ (y - -3)² = 4(-3/2) (x - 7/2)

∴ (y + 3)² = -6(x - 7/2) ⇒ in standard form

* The equation of the parabola is (y + 3)² = -6(x - 7/2)

f(x) = - 2/3x + 5; f(5/2)

substitute 5/2 in for x:

f(5/2) = -2/3(5/2) + 5

simplify the right side:

f(5/2) = -5/3 + 5

f(5/2) = 10/3

answer:

f(5/2) = 10/3

i hope this you!

maximum area = xy = (16)(32) = 512 ft2

to maximize the area of the garden, the side of the fence parallel to the side of the house should be 32 ft long, and the other two sides should both have length 16 ft.'

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