Mathematics High School

Derive the equation of the parabola with a focus at (0, 1) and a directrix of y = -1.c

Answers

Answer 1

Answer:

[tex]\displaystyle y=\frac{1}{4}x^2[/tex]

Step-by-step explanation:

Let (x, y) be a point on the parabola.

By definition, any point on the parabola is equidistant from the focus and the directrix

The distance from the focus is given by:

[tex]\begin{aligned} d&=\sqrt{(x-0)^2+(y-1)^2\\\\&=\sqrt{x^2+(y-1)^2}\end{aligned}[/tex]

The distance from the directrix is given by:

[tex]d=|y-(-1)|=|y+1|\text{ or } |-1-y|[/tex]

So:

[tex]\sqrt{x^2+(y-1)^2}=|y+1|^[/tex]

Square both sides. Since anything squared is positive, we can remove the absolute value:

[tex]x^2+(y-1)^2=(y+1)^2[/tex]

Square:

[tex]x^2+(y^2-2y+1)=y^2+2y+1[/tex]

Hence:

[tex]x^2=4y[/tex]

So, our equation is:

[tex]\displaystyle y=\frac{1}{4}x^2[/tex]

Related Questions

Which of the following is the equation of a line that passes though the points (2,5) and (4,3)

Answers

Answer:

y= -1x+7

y = -1x + b

Step-by-step explanation:

You want to find the equation for a line that passes through the two points:

(2,5) and (4,3).

First of all, remember what the equation of a line is:

y = mx+b

Where:

m is the slope, and

b is the y-intercept

First, let's find what m is, the slope of the line...

The slope of a line is a measure of how fast the line "goes up" or "goes down". A large slope means the line goes up or down really fast (a very steep line). Small slopes means the line isn't very steep. A slope of zero means the line has no steepness at all; it is perfectly horizontal.

For lines like these, the slope is always defined as "the change in y over the change in x" or, in equation form:

So what we need now are the two points you gave that the line passes through. Let's call the first point you gave, (2,5), point #1, so the x and y numbers given will be called x1 and y1. Or, x1=2 and y1=5.

Also, let's call the second point you gave, (4,3), point #2, so the x and y numbers here will be called x2 and y2. Or, x2=4 and y2=3.

Now, just plug the numbers into the formula for m above, like this:

3 - 5

4 - 2

or...

-2

or...

m=-1

So, we have the first piece to finding the equation of this line, and we can fill it into y=mx+b like this:

y=-1x+b

Now, what about b, the y-intercept?

To find b, think about what your (x,y) points mean:

(2,5). When x of the line is 2, y of the line must be 5.

(4,3). When x of the line is 4, y of the line must be 3.

Because you said the line passes through each one of these two points, right?

Now, look at our line's equation so far: y=-1x+b. b is what we want, the -1 is already set and x and y are just two "free variables" sitting there. We can plug anything we want in for x and y here, but we want the equation for the line that specfically passes through the two points (2,5) and (4,3).

So, why not plug in for x and y from one of our (x,y) points that we know the line passes through? This will allow us to solve for b for the particular line that passes through the two points you gave!.

You can use either (x,y) point you want..the answer will be the same:

(2,5). y=mx+b or 5=-1 × 2+b, or solving for b: b=5-(-1)(2). b=7.

(4,3). y=mx+b or 3=-1 × 4+b, or solving for b: b=3-(-1)(4). b=7.

See! In both cases we got the same value for b. And this completes our problem.

The equation of the line that passes through the points

(2,5) and (4,3)

y=-1x+7

A hot air balloon is released and it rises at a speed of 15 mph. A

weather pattern introduces a wind headed west at 20 mph. The

hot air balloon is now redirected. What is the new direction of the

hot air balloon?

Answers

Answer:

The direction is 37 degree north of west.

Step-by-step explanation:

velocity of balloon, v = 15 mph upwards

velocity of wind, v' = 20 mph west wards

The direction is given by

[tex]tan\theta = \frac{15}{20}\\\\\theta = 37^o north of west[/tex]

Draw a graph of the linear equations x – 4y + 10 = 0 and x + 4y – 10 = 0. Find the coordinates of the vertices of the triangle formed by these lines along with the X-axis

Answers

Step-by-step explanation:

x-14y=0

x=0/14y

x=14y

14y

The first equation crosses the x axis at x - 4 x 0 + 10 = 0 => x = -10

The second equation crosses the x axis at x + 4 x 0 - 10 = 0 => x = +10

Adding the equations together gives 2x = 0 => x = 0
0 + 4y - 10 = 0 => 4y = 10 => y = 2.5

The vertices of the triangle formed by the two lines and the x axis are (-10, 0) (10, 0) and (0, 2.5)

find the volume of the rectangle

Answers

Answer:

3/16

Step-by-step explanation:

simply multiply all 3 numbers

What is the value of x in the diagram?

Answers

Answer:

x = 30

Step-by-step explanation:

here 50 is hypotenuse as it is opposite of 90 degree.

x and x + 10 are the two other smaller sides of a right angled triangle respectively.

using pythagoras theorem,

a^2 + b^2 = c^2

x^2 + (x + 10)^2 = 50^2

x^2 + x^2 + 20x + 100 = 2500

2x^2 + 20x + 100 = 2500

2x^2 + 20x + 100 - 2500 = 0

2x^2 + 20x - 2400 = 0

2(x^2 + 10x - 1200) = 0

x^2 + 10x - 1200 = 0

x^2 + (40 - 30) - 1200 = 0

x^2 + 40x - 30x - 1200 = 0

x(x + 40) - 30(x + 40x) = 0

(x + 40)(x - 30) = 0

either x + 40 = 0 OR x - 30 = 0

x = 0 - 40

x = -40

x - 30 = 0

x = 30

x = -40,30

since the length and distance is not measured in negative ur answer will be 30

credit goes to sreedevi102

thank u very much . At first i was wrong and giannathecookie i m really sorry

Answer:

x = 30

Step-by-step explanation:

Using Pythagoras Theorem:

[tex]x^2 + ( x+ 10)^ 2 = 50^2\\\\x^2 + (x^2 + 100 + 20x ) = 2500\\\\x^2 + x^2 + 20x = 2500 - 100 \\\\2x^2 + 20x = 2400\\\\2x^2 + 20x - 2400 = 0\\\\2(x^2 + 10x - 1200) = 0\\\\x^2 + 10x - 1200 = 0\\\\x^2 + 40x - 30x - 1200 = 0\\\\x(x + 40 ) -30(x + 40) = 0\\\\(x+40)(x - 30) = 0\\\\x = -40, \ x = 30[/tex]

Since x is the measurement of a side, it can't be negative. Therefore x = 30

You are baking a cake. The recipe asks for \frac{3}{5} 5 3 cup of butter and you want to make \frac{1}{5} 5 1 of the original recipe. How many cups of butter will you need?

Answers

Answer:

3/25 cup of butter

Step-by-step explanation:

You are baking a cake. The recipe asks for 3/5 cup of butter and you want to make 1/5 of the original recipe.

The calculation for the above question is given below:

1 recipe = 3/5 cup of butter

1/5 recipe = x

Cross Multiply

x × 1 recipe = 1/5 recipe × 3/5 cup of butter

x = 1/5 recipe × 3/5 cup of butter /1 recipe

x = 3/25 cup of butter

Therefore, you will need 3/25 cup of butter

decide which point lies on the line that is parallel to AB and passes through point P

Answers

the answer is B because PG is parallel to AB

PLEASE HELP WILL MARK BRAINLIEST

Answers

WHERES THE QUESTION IT WONT SHOW UP ON MY SCREEN POST IT AGAIN

Select the graph that would represent the best presentation of the solution set.
|xl > 5

Answers

There isn’t a picture but I think the answer is the one in the picture I attached.

If Devon took 20 min to drive 24 km, what was his R.O.C.? Answer in decimals.

Answers

Answer:

1.2 km/min

Step-by-step explanation:

ROC? rate of change? if not rate of change than my answer may not be correct

24km/20min = 1.2 km/min

24km/20min * 60min/1 hr= (24*60)/20=120 km/hr

if p(x) = x^3 + 1 is divided by (x + 2) , then the remainder is
PLS HELP!

Answers

Answer:

[tex]{ \bf{factor : x + 2}} \\ { \tt{divisor = - 2 }} \\ { \bf{f(x) = {x}^{3} + 1 }} \\ { \bf{f( - 2) = {( - 2)}^{3} + 1}} \\ { \bf{remainder = - 7}}[/tex]

Please help I’ll give brainliest

Answers

Answer:

Answer is 670000 If you can please give me brainliest

4. If you color the perfect squares on a multiplication table, you will be coloring a_______ line.

A. Diagonal
B. Vertical
C. Horizontal
D. Zig-zag

Please helpppp

Answers

Answer:

A. Diagonal line

Answer:

i think itsssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss

sssssssssssssssssssssssssssssss

ssssssssssssssssssssssssss

sssssssssssssssssssssssssssssss

hmmmmmm i dont know

Step-by-step explanation:

Assignment
1
Which is rational?
a. 64
b. 17
C. 67.714819...
22. Which is irrational?
a. 75.106
c. 101
Identify each of the following as Rational or Irrational.
3 -42
4 65.4279
5
98
16
6
25
7 57.013013..
8
18.44333777...
9
-139.04
24
10

Answers

It is irrational 33 anwser is a

Help are these correct ahahahahhh and explain pls

Answers

Both answers are corrrect!

Jeremy has heard a lot of people in the club talking about tackling a 950-foot rock formation. Jeremy has set a limit that they won’t climb anything that takes longer than 7 hours, so they have enough time to travel to and from the place. Will it be possible to climb a 950-foot rock formation within Jeremy’s time constraint? Explain why or why not.

Answers

You would need to know the rate at which Jeremy climbs to determine your answer.

Answer: no Jeremys time is not constraint

Step-by-step explanation: The amount of minutes to climb up 1 foot of height would take around 2 to 3 minutes, however if you divide 950 with 2 you will get 475 minutes to climb, if we also convert to 475 into hours that will be 7.92 hours . so overall he will climb extra 92 minutes (i really hope this kinda helped)

Math help due soon thanks

Answers

Answers:

SkippingSee the diagram belowx = 7No they are not similar

=======================================

Explanation:

SkippingWe peel the triangles apart as shown below. There's not much to say about it. The only thing I can think is that the larger horizontal side is 8+6 = 14 m.Due to the similar triangles, we can form the proportion x/4 = 14/8. The 14 is from 8+6. Cross multiplying leads to 8x = 56 which solves to x = 7.Focus on the triangle on the left. The missing angle is 180-95-35 = 50 degrees. The missing angle for the triangle on the right is 180-35-60 = 85 degrees. The angles don't all match up, so the triangles aren't similar.

CAN SOMEONE HELP THANKS 14 POINTS

Answers

Answer:

6,9,12

Step-by-step explanation:

A triangle cannot be considered a triangle unless the sum of the smaller two of the sides is greater than the larger side.

Answer:

(6, 9, 12)

Hope that this helps!

Which of the following are not polynomials? O A. x2 +x+1 O B. X-2 + x + 1 am. x + V3x+1 OD. 3+x+1 E. x + 0x2 + 2x + 2

Answers

Answer:

Option B

Step-by-step explanation:

Look.......Polynomial is something which has more than 3 term..So, as you can see option B has more than three.

Through (1,0) slope = -1

Answers

Answer:

y = -1x+1

Step-by-step explanation:

The equation for a line in slope intercept form is

y = mx+b where m is the slope and b is the y intercept

y = -1x+b

Substitute in the point

0 = -1(1) +b

0 = -1+b

1 = b

The equation is

y = -1x+1

Find the equation of the line that passes through the points (4,
11) and (-1,1). Write your answer in slope-intercept form. Bonus points for
writing it in the two other forms (make sure you label which form is which).

Answers

Step-by-step explanation:

the slope = (1-11)/(-1-4) = -10/(-5) = 2

the equation is : y -11 = 2(x-4)

=> y -11 = 2x -20

y = 2x -8 +11

y = 2x +3

other forms :

<=> 2x - y = -3

<=> 2x - y + 3 = 0

WILL MARK BRAINLIST!!

Answers

Answer:

24 units

Step-by-step explanation:

Look at the coordinate plane. First start with the bottom side (LN). The line goes from -3 to 9. This means that the line is 12 units long. Now, look at the other sides. MN goes from 3 to 9, therefore, the line is 6 units long. Lastly, look at ML— -3 to 3, therefore, the line is 6 units long. Add them all up, (12+6+6) and it equals 24 units.

24 units

////////////

Last week, a family ordered dinner through a local food delivery service. The food was $45. They had a coupon for 15% off the total bill.
The bill was $
when the coupon was applied.

Answers

$38.25) you multiple 45 by .15 then subtract the product from 45 and get your answer

Which expression is equivalent to 27 Σ 8n? N=0 hurry please my life depends on it

Answers

Given:

The expression is:

[tex]\sum\limits_{n=0}^{27}8n[/tex]

To find:

The expression that is equivalent to the given expression.

Solution:

According to the property of summation:

[tex]\sum\limits_{n=0}^{k}Cn=C\sum\limits_{n=0}^{k}n[/tex]

Where, C is a constant.

We have,

[tex]\sum\limits_{n=0}^{27}8n[/tex]

Using the above mentioned property of summation, we get

[tex]\sum\limits_{n=0}^{27}8n=8\sum\limits_{n=0}^{27}n[/tex]

The expression [tex]8\sum\limits_{n=0}^{27}n[/tex] is equivalent to the given expression.

Therefore, the correct option is C.

Which expression is the same as 1 ten, 3 ones, and 9 thousandths?
Choose 1 answer:

Answers

Answer:

"B"

Step-by-step explanation:

If x^151+ 100 is divided by x+1 then the remainder is

Answers

Answer: 11 because it all works out.

How to find the slope of a line passing through (-3,3) , (-5,9)

Answers

Answer:

slope = - 3

Step-by-step explanation:

[tex]slope, m = \frac{y_2 - y_1}{x_2 - x_ 1}[/tex] , [tex][ \ (x_ 1 , y_ 1 ) = ( -3 , 3 ) , \ (x_2 , y _ 2 ) = ( - 5 , 9 ) \ ][/tex]

[tex]slope = \frac{9 - 3}{-4 - ( -3 )} = \frac{6}{-5 + 3} = \frac{6}{-2} = -3[/tex]

6×²+3×y-2a×-ay (need answers)

Answers

Answer:

(If the x means the variable in your equation) 2a^2y+6x^2+3xy

Step-by-step explanation:

We have to simplify the equation to find the answer

6x^2+3xy−2a(−a)y

=6x^2+3xy+2a^2y

Using √6241=79, Find the value of √62.41

Answers

Answer:

[tex] \blue{7.9} [/tex]

Step-by-step explanation:

[tex] \sqrt{6241} = 79 [/tex]

[tex] \sqrt{62.41} = [/tex]

[tex] = \sqrt{\dfrac{6241}{100} [/tex]

[tex] = \dfrac{79}{10}[/tex]

[tex] = \blue{7.9} [/tex]

she does 3 sets of 8 pushups 7 days a week, how many pushups does she do in one week

Answers

Answer:

24 push ups

3 x 8 = 24

ksjsjsowjsnsoajjsodhew

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