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4 years ago

Simplify the expression. (3 points) -5+i/2i WILL GIVE BRAINLY

1 answer:

6 0

$\bf recall~that\qquad i^2=-1\\\\
-------------------------------\\\\
\cfrac{-5+i}{2i}\cdot \cfrac{i}{i}\implies \cfrac{i(-5+i)}{2i^2}\implies \cfrac{-5i+i^2}{2(-1)}\implies \cfrac{-5i+(-1)}{-2}
\\\\\\
\cfrac{-5i-1}{-2}\implies \cfrac{1+5i}{2}$

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What dimensions will produce a square-based box, of minimum surface area, with volume of

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Answer:

the total surface of the box is 486 cm 2

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2 years ago

A restaurant has r reservations each hour except it's last hour, when it has 5 reservations. If the restaurant is open for six h

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R = 55 total reservations - 5 reservations from the last hour / 5 hours

R = 55 -5 / 5

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3 years ago

Read 2 more answers

"Select the equation of the least squares line for the data: (34.0, 1.30), (32.5, 3.25), (35.0, .65), (31.0, 6.50), (30.0, 5.85)

yulyashka [42]

Answer:

$y=-1.055 x +37.643$

And the best option would be:

a. ŷ= 37.643-1.0543x

Step-by-step explanation:

We assume that the data is this one:

x: 34.0, 32.5, 35.0, 31.0, 30.0, 27.5, 29.0

y: 1.30, 3.25, 0.65, 6.50, 5.85, 8.45, 6.50

Find the least-squares line appropriate for this data.

For this case we need to calculate the slope with the following formula:

$m=\frac{S_{xy}}{S_{xx}}$

Where:

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}{n}$

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}$

So we can find the sums like this:

$\sum_{i=1}^n x_i = 34.0+ 32.5+ 35.0+ 31.0+ 30.0+ 27.5+ 29.0
=219$

$\sum_{i=1}^n y_i =1.3+3.25+0.65+6.5+5.85+8.45+6.5=32.5$

$\sum_{i=1}^n x^2_i = 34.0^2+ 32.5^2+ 35.0^2+ 31.0^2+ 30.0^2+ 27.5^2+ 29.0^2
=6895.5$

$\sum_{i=1}^n y^2_i =1.3^2+3.25^2+0.65^2+6.5^2+5.85^2+8.45^2+6.5^2=202.8$

$\sum_{i=1}^n x_i y_i =34*1.3 + 32.5*3.25+ 35*0.65+ 31*6.5+30*5.585 +27.5*8.45 +29*6.5=970.45$

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=6895.5-\frac{219^2}{7}=43.929$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}{n}=970.45-\frac{219*32.5}{7}=-46.336$

And the slope would be:

$m=-\frac{46.336}{43.929}=-1.055$

Nowe we can find the means for x and y like this:

$\bar x= \frac{\sum x_i}{n}=\frac{219}{7}=31.286$

$\bar y= \frac{\sum y_i}{n}=\frac{32.5}{7}=4.643$

And we can find the intercept using this:

$b=\bar y -m \bar x=4.643-(-1.055*31.286)=37.643$

So the line would be given by:

$y=-1.055 x +37.643$

And the best option would be:

a. ŷ= 37.643-1.0543x

5 0

4 years ago

Starting with 13 grams of starch, what percentage is left when 6 grams remain? Write your answer to two decimal points.

topjm [15]

Answer:

46.15%

Step-by-step explanation:

(6 ÷ 13) × 100 = 46.15384615

= 46.15%

4 0

3 years ago

If a line passes through the points (2.5,2.5) and (3.5,5.5), the equation of the line is y-5.5 = 3(x- blank ).

timurjin [86]

Answer:

(x- 2.5)

Step-by-step explanation:

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3 years ago

Read 2 more answers