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3 years ago

What are the focus and directrix of the parabola with the equation y=1/16x^2

1 answer:

8 0

Y=1/16x^2
multiplying both sides by 16 we get:
16y=x^2
The general form of a parabola is:
(x-h)^2=4p(y-k)
thus
4p=16
p=4
The parabola opens upwrd:
Focus: (h,k-p)
(0,0-4)
=(0,-4)
Directrix: y=-4

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I would take her 30 minutes

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3 years ago

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2 years ago

Here is a simple probability model for multiple-choice tests. Suppose that each student has probability p of correctly answering

Alla [95]

Answer:

a) The probability that Jodi scores 78% or lower on a 100-question test is 4%.

b) The probability that Jodi scores 78% or lower on a 250-question test is 0.023%.

Step-by-step explanation:

a) To approximate this distribution we have to calculate the mean and the standard distribution.

The mean is the proportion p=0.85.

The standard deviation can be calculates as:

$\sigma=\sqrt{\frac{p(1-p)}{n} }= \sqrt{\frac{0.85*(1-0.85)}{100} }=0.04$

To calculate the probability that Jodi scores 78% or less on a 100-question test, we first calculate the z-value:

$z=\frac{p-p_0}{\sigma} =\frac{0.78-0.85}{0.04} =-1.75$

The probability for this value of z is

$P(x$

The probability that Jodi scores 78% or lower on a 100-question test is 4%.

b) In this case, the number of questions is 250, so the standard deviation needs to be calculated again:

$\sigma=\sqrt{\frac{p(1-p)}{n} }= \sqrt{\frac{0.85*(1-0.85)}{250} }=0.02$

To calculate the probability that Jodi scores 78% or less on a 250-question test, we first calculate the z-value:

$z=\frac{p-p_0}{\sigma} =\frac{0.78-0.85}{0.02} =-3.5$

The probability for this value of z is

$P(x$

The probability that Jodi scores 78% or lower on a 250-question test is 0.023%.

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2 years ago

What is 3/4 plus 4 1/3

OlgaM077 [116]

Answer:

Step-by-step explanation:

You need to change the denominator into a the least common denominator, 4 and 3 both have 12 in common. 12 is your new denominator but what you to the bottom you must do to the top. So when you multiply 3/4 by 3/3 you will get 9/12.

Then you want to make 4 1/3 into a improper fraction, which would be 13/3 you want to multiply this by 4 and you will get 52/12. You will then add 52/12 to 9/12 and get 61/12 or 5 1/12.

If you need any more help please let me know.

4 0

3 years ago

A circular garden is enlarged so that the new diameter is twice the old diameter. What is the ratio of the original area to the

Amanda [17]

Answer:

Explained briefly below.

Step-by-step explanation:

<u>For old circular garden:</u>

take the radius as r.

then use the formula to find area of circle: πr² ......this is old garden area.

<u>For new enlarged garden:</u>

the radius is twice the old radius so, radius = 2 * r = 2r ......enlarged radius

now find area for this new garden: π(2r)² → 4πr²

In common fractions: (old garden)/(new garden)

: ( πr² ) / ( 4πr² )

: 1/4

7 0

2 years ago

Read 2 more answers