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frez [133]
2 years ago
12

Write the equation of a parabola with focus at (1,-4) and a directrix at X=2

Mathematics
1 answer:
konstantin123 [22]2 years ago
3 0

Answer:

The equation of a parabola is

x =  \frac{1}{4(f - h)} (y - k) ^{2}  + h

Step-by-step explanation:

(h,k) is the vertex and (f,k) is the focus.

Thus, f = 1, k = −4.

The distance from the focus to the vertex is equal to the distance from the vertex to the directrix: f - h = h - 2.

Solving the system, we get h = 3/2, k = -4, f = 1.

The standard form is:

x =  -  \frac{y ^{2} }{2}  - 4y -  \frac{13}{2}

The general form is:

2x +  {y}^{2}  + 8y + 13 = 0

The vertex form is:

x =  -  \frac{(y + 4) ^{2} }{2}  +  \frac{3}{2}

The axis of symmetry is the line perpendicular to the directrix that passes through the vertex and the focus: y = -4.

The focal length is the distance between the focus and the vertex: 1/2.

The focal parameter is the distance between the focus and the directrix: 1.

The latus rectum is parallel to the directrix and passes through the focus: x = 1.

The length of the latus rectum is four times the distance between the vertex and the focus: 2.

The eccentricity of a parabola is always 1.

The x-intercepts can be found by setting y = 0 in the equation and solving for x.

x-intercept:

( -  \frac{13}{2}  \: ,0)

The y-intercepts can be found by setting x = 0 in the equation and solving for y.

y-intercepts:

(0, - 4 -  \sqrt{3)}

(0, - 4 +  \sqrt{3)}

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inn [45]

<u>Answer:</u>

Point Form:

(−5,1)

Equation Form:

x=−5, y=1

<u>Step-by-step explanation:</u>

Solve for the first variable in one of the equations, then substitute the result into the other equation.

1.  x=5y−10

2. 20y−30=−10

3. y=1

4. x=−5

4 0
3 years ago
the local high school has 19 honored students for every 81 non-honored students if there are 750 students in the school how many
aliina [53]

I got 176 I sad 750÷19 = 176

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3 years ago
If $48,000 is invested in an account earning 3.1% interest compounded continuously, determine how long it will
Bas_tet [7]

Answer:

It will take about 35.439  years to triple.

Step-by-step explanation:

Recall the formula for continuously compounded interest:

A=P\,e^{r*t}

where "A" is the total (accrued or future) accumulated value, "r" is the rate (in our case 0.031 which is the decimal form of 3.1%), "P" is the principal, and "t" is the time in years (our unknown).

Notice also that even that the final amount we want to get is three times $48,000. So our formula becomes:

3\,*\,48,000=\,48,000\,\,e^{0.031\,*t}\\\frac{3\,*\,48,000}{48,000} =e^{0.031*t}\\3=e^{0.031*t}

Now,in order to solve for "t" (which is in the exponent, we use logarithms:

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7 0
3 years ago
Work out the lengh of RS <br> gue your answer to 3 significant figures
atroni [7]

Answer:

RS ≈ 5.83 units

Step-by-step explanation:

Calculate RS using the distance formula

d = √ (x₂ - x₁ )² + (y₂ - y₁ )²

with (x₁, y₁ ) = R(- 3, 1) and (x₂, y₂ ) = S(2, 4)

RS = \sqrt{(2+3)^2+(4-1)^2}

     = \sqrt{5^2+3^2}

     = \sqrt{25+9}

     = \sqrt{34} ≈ 5.83 ( to 3 significant figures )

8 0
3 years ago
Evaluate the expression. 5^2. what is the value of the expression?​
vovangra [49]

Answer:

25

Step-by-step explanation:

Any numbers to the 2nd powered are always squared. Whenever you are given an exponent, the base is the number that you multiply, and the power is one more than how many times you multiply the base number together. In this case, you multiply five by itself once to get 25 as your answer.

7 0
3 years ago
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