We know that
the equation of the parabola is of the form
y=ax²+bx+c
in this problem
y=1/4x²−x+3
where
a=1/4
b=-1
c=3
the coordinates of the focus are
(-b/2a,(1-D)/4a)
where D is the discriminant b²-4ac
D=(-1)²-4*(1/4)*3-----> D=1-3---> D=-2
therefore
x coordinate of the focus
-b/2a----> 1/[2*(-1/4)]----> 2

y coordinate of the focus
(1-D)/4a------> (1+2)/(4/4)---> 3

the coordinates of the focus are (2,3)

3 0

2 years ago

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Percentage grade averages were taken across all disciplines at a particular university, and the mean average was found to be 83.

Georgia [21]

Correct Ans:
Option A. 0.0100

Solution:
We are to find the probability that the class average for 10 selected classes is greater than 90. This involves the utilization of standard normal distribution.

First step will be to convert the given score into z score for given mean, standard deviation and sample size and then use that z score to find the said probability. So converting the value to z score:

$z-score= \frac{90-83.6}{ \frac{8.7}{ \sqrt{10} } } \\ \\ 
z-score =2.326$

So, 90 converted to z score for given data is 2.326. Now using the z-table we are to find the probability of z score to be greater than 2.326. The probability comes out to be 0.01.

Therefore, there is a 0.01 probability of the class average to be greater than 90 for the 10 classes.

5 0

3 years ago

Hi can someone please help me?

jasenka [17]

Evaluate.
1934917632
this is evaluation

8 0

2 years ago

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I wander what the quadramatic fourmula is

Marrrta [24]

Definition of quadratic a formula
= a formula that gives the solutions of the general quadratic equation ax2 + bx + c = 0 and that is usually written in the form x = (-b ± √(b2 − 4ac))/(2a)

4 0

2 years ago

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