Question

If the line D: x = 1 is the directrix of the parabola p: y raised to the power of 2 - kx + 8 = 0, then one of the values of k can be:

198

likes
988 views

Answer to a math question If the line D: x = 1 is the directrix of the parabola p: y raised to the power of 2 - kx + 8 = 0, then one of the values of k can be:

Expert avatar
Jayne
4.4
106 Answers
### Step-by-Step Solution:

### Step 1: Rewrite the parabola equation in standard form

y^2 = kx - 8

### Step 2: Identify vertex form and properties of the parabola

p = \frac{k}{4}

### Step 3: Determine the vertex

\left(\frac{8}{k}, 0\right)

### Step 4: Location of the directrix

The directrix is at:

x = \frac{8}{k} - \frac{k}{4}

Given the directrix is \( x = 1 \):

\frac{8}{k} - \frac{k}{4} = 1

Simplify and solve the equation:

8 - \frac{k^2}{4} = k

\frac{k^2}{4} + k - 8 = 0

k^2 + 4k - 32 = 0

### Step 5: Solve the quadratic equation

Use the quadratic formula \( k = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \):

k = \frac{-4 \pm \sqrt{144}}{2}

k = \frac{-4 \pm 12}{2}

Thus, the solutions are:

k = \frac{-4 + 12}{2} = 4

k = \frac{-4 - 12}{2} = -8

Verify which value matches the directrix condition:

- For \( k = 4 \):

\frac{8}{4} - \frac{4}{4} = 2 - 1 = 1

This matches.

- For \( k = -8 \):

\frac{8}{-8} - \frac{-8}{4} = -1 + 2 = 1

This also matches.

Therefore, \( k = 4 \) satisfies the condition.

\boxed{k = 4}

Frequently asked questions (FAQs)
What is the equation for calculating the circumference of a circle?
+
What is the maximum value that a continuous function defined on a closed and bounded interval can take on?
+
Math question: In a group of 10 people, how many ways can you choose a committee of 3 people? (
+
New questions in Mathematics
A=m/2-t isolate t
-442/c+5=26 what is c?
If L (-2, -5) reflected across y = -4. What are the coordinates of L?
132133333-33
The data set (75, 85, 58, 72, 70, 75) is a random sample from the normal distribution No(µ, σ). Determine a 95% two-sided confidence interval for the mean µ .
Director of reservations believes that 9% of the ticketed passengers are no-shows. If the directors right what is the probability that the proportion of no-shows in a sample of 789 ticketed passengers with differ from the population proportion buy more than 3% round your answer to four decimal places.
Suppose a large shipment of cell phones contain 21% defective. If the sample of size 204 is selected, what is the probability that the sample proportion will differ from the population proportion by less than 4% round your answer to four decimal places
2x-4y=-6; -4y+4y=-8
Raúl, Gilberto and Arturo are playing golf; The probabilities of winning for each one are as follows: (Raúl wins) = 20% (Gilberto wins) = 0.05% (Arturo wins) = ¾%. Perform operations and order events from least to most probable.
7=-4/3y -1
Use the sample data and confidence level given below to complete parts​ (a) through​ (d). A drug is used to help prevent blood clots in certain patients. In clinical​ trials, among 4336 patients treated with the​ drug, 194 developed the adverse reaction of nausea. Construct a ​99% confidence interval for the proportion of adverse reactions.
TEST 123123+1236ttttt
4+168×10³×d1+36×10³×d2=-12 -10+36×10³×d1+72×10³×d2=0
Determine the increase of the function y=4x−5 when the argument changes from x1=2 to x2=3
Solve equations by equalization method X-8=-2y 2x+y=7
Determine a general formula​ (or formulas) for the solution to the following equation.​ Then, determine the specific solutions​ (if any) on the interval [0,2π). cos30=0
A hardware bill totals $857.63 with discounts of 5% and 3%. What is the net cost of the Material ?
Two particles of electrical charges Q1=3.8×10-⁶C and q,=4.4×10-⁶C are separated in vacuum by a distance of 4.0.10-⁸ m. Since K=9.0.10⁹ N.m²/C², the intensity of the interaction force between them, in newtons, is?
What is the total amount due and the amount of interest on a 3-year loan of $1,000 at a simple interest rate of 12% per year?
Solve the following 9x - 9 - 6x = 5 + 8x - 9