Simplify ---(2√7)^2

Mathematics

1 answer:

PolarNik [594]3 years ago

5 0

$(2 \sqrt{ {7} } )^{2} = {2 }^{2} \times 7 = 4 \times 7 = 28$

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What is the equation of a parabola with (−2, 4) as its focus and y = 6 as its directrix? Enter the equation in the box.

SOVA2 [1]

Notice the picture below

the directrix is above the focus point, meaning the parabola is vertical and is opening downwards

now, "p" is the distance from the vertex to the focus point or the directrix, so that means, the vertex is between those two fellows, over the axis of symmetry, x = -2, since "p" is 1 unit, that puts the vertex at -2,5

since the parabola is opening downwards, that means the "p" value is negative, so is -1

$\bf \textit{parabola vertex form with focus point distance}\\\\
\begin{array}{llll}
(y-{{ k}})^2=4{{ p}}(x-{{ h}}) \\\\
\boxed{(x-{{ h}})^2=4{{ p}}(y-{{ k}}) }\\
\end{array}
\qquad 
\begin{array}{llll}
vertex\ ({{ h}},{{ k}})\\\\
{{ p}}=\textit{distance from vertex to }\\
\qquad \textit{ focus or directrix}
\end{array}\\\\
-----------------------------\\\\$

$\bf \begin{cases}
p=-1\\
h=-2\\
k=5
\end{cases}\implies (x-(-2))^2=4(-1)(y-5)
\\\\\\
(x+2)^2=-4(y-5)\implies 
-\cfrac{1}{4}(x+2)^2=y-5
\\\\\\
\boxed{-\cfrac{1}{4}(x+2)^2+5=y}$

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3 years ago

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mestny [16]

Its 0.5793 with the bar over the 3

3 0

3 years ago

The population of scores on a nationally standardized test forms a normal distribution with μ = 300 and σ = 50. If you take a ra

madreJ [45]

Answer:

$P(\bar X$

And using a calculator, excel or the normal standard table we have that:

$P(Z$

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Solution to the problem

Let X the random variable that represent the scores of a population, and for this case we know the distribution for X is given by:

$X \sim N(300,50)$