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Readme [11.4K]
4 years ago
9

(URGENT)use the vectors to determine two dot products​

Mathematics
1 answer:
MAXImum [283]4 years ago
4 0

u = 9 i - 6 j

v = -3 i - 2j

w = 19 i + 15 j

u • v = (9 i - 6 j) • (-3 i - 2j)

Distribute the dot products:

u • v = 9*(-3) (i • i) + 9*(-2) (i • j) + (-6)*(-3) (j • i) + (-6)*(-2) (j • j)

i and j are orthogonal unit vectors, so their dot products are 0, while i • i = j • j = 1. So we have

u • v = 9*(-3) + (-6)*(-2) = -27 + 12 = -15

In other words, the dot product can be computed by simply multiplying corresponding components, and taking the total.

u • w = 9*19 + (-6)*15 = 81

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Suppose that AB and EF are corresponding sides of similar triangles. If AB=2 and the scale factor is 5, what is EF?
Zina [86]

Answer:

EF=10

Step-by-step explanation:

If they are corresponding,

AB = 2 x Scale factor of 5 = 10

8 0
3 years ago
Elena has written 3 sports books for kids. One book is about soccer, one is about baseball, and one is about basketball. Elena h
Mamont248 [21]

Answer:

1293 soccer books

Step-by-step explanation:

The tricky part about questions like this is: how do I assign variables to the three types of book?

You get a clue from the sentence, "She sold 3 times as many copies of the soccer book as the baseball book."  The number of soccer books is being described by referring TO the number of baseball books.  Pick a variable and assign it to the item being REFERRED TO!

x = number of baseball books

Then  3x = number of soccer books.  The number of basketball books is the same, so 3x = number of basketball books.  Here's the list...

x = number of baseball books

3x = number of soccer books

3x = number of basketball books

The total of these is 3017, so

x + 3x + 3x = 3017

7x = 3017

x = 431

Ah!  But don't forget to look back at the question:  it asks for the number of SOCCER books!  That's 3x, so 3(431) = 1293.

5 0
3 years ago
Find the percent of area under a normal curve between the mean and the given number of standard deviations from the mean.​ (Note
coldgirl [10]

Answer:

15.86%

Step-by-step explanation:

When the distribution is normal, we use the z-score formula.

In a set with mean \mu and standard deviation \sigma, the zscore of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Percent of area between the mean and 0.20 standard deviations from the mean:

pvalue of Z = 0.2 subtracted by the pvalue of Z = -0.2

Z = 0.2 has a pvalue of 0.5793

Z = -0.2 has a pvalue of 0.4207

0.5793 - 0.4207 = 0.1586

So this percentage is 15.86%

8 0
4 years ago
There were 5 cookies and 3 were gone how many are left
qwelly [4]
Answer: 2 cookies are left

Explanation: I ate the other three :|
7 0
3 years ago
Read 2 more answers
Please answer the ones i have not!
BigorU [14]

Answer:

y = 2/3 (34) + 20 = 34

y = (3 x -2)^2 +17 = 54

y = 2.5 (0.6) + 5.8 = 7.3

Step-by-step explanation:

to make it clear on the solution box you are going to write -----

#2) 34

#3) 54

#4) 7.3

6 0
3 years ago
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