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3 years ago

HELP!! Im not sure what i did wrong!!

Mathematics

1 answer:

Igoryamba3 years ago

7 0

I'm not sure what exactly you did wrong, but I agree with you that the sample size is too small, so the correct answer will probably be the fourth options. Hope that this gives you some confidence, and 'm sorry not to be able to help you any further...

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Help me ASAP PLEASE

lina2011 [118]

Answer:

4. Functions: 1, 2, 4, 5, 7, 8, 11, 12

5. y = -1/2x+5/2, x ≤ -1; 2x +1, x > -1.

y = 2, x < 0; x, 0 ≤ x ≤ 3; 3 x > 3.

Step-by-step explanation:

4. A list of ordered pairs is a function of no x-values are re-used. In (3) and (6), the value x=2 is used more than once.

A graph represents a function if it passes the "vertical line test." A vertical line cannot intersect the graph in 2 or more points. (9) and (10) both fail that test.

If the relation is not listed here as being "not a function," then it is one of the answers to question 4.

5. The first step in writing the equation of a piecewise function is to identify the pieces. These are generally bounded by points of discontinuity--jumps in the function value, or changes in the slope of lines.

The second step is to identify the section of the function that boundary points belong to. Solid dots are part of the function definition; open circles are not.

<u>Left Graph</u>

The left piece ends at x=-1. There is a solid dot attached to the left piece, so its definition will be for the domain x ≤ -1. That line has slope -1/2, since is drops 1 unit for each 2 to the right. If extended, it would intersect the y-axis at y = 2 1/2 = 5/2. So, the piece on the left is y = -1/2x + 5/2 for x ≤ -1.

The right piece starts at x=-1, but does not include that point. It has a rise of 2 for each 1 to the right, so its slope is 2. It crosses the y-axis at y=1, so the piece on the right is y = 2x + 1 for x > -1.

You can use the method of your textbook author to combine theses pieces into one equation. The method shown above is one way to do it.

<u>Right Graph</u>

This graph has a discontinuity at x=0 and a change in slope at x=3. It can be described by 3 pieces. The point at x=0 does not belong to the left piece, but goes with the middle piece.

The left piece of the function is the constant 2, so has the equation y = 2 for x < 0.

The middle piece has a slope of 1 and a y-intercept of 0, so has the equation y = x for 0 ≤ x ≤ 3.

The point at x=3 belongs to both the middle piece and the right piece, so can be part of both function definitions, if you like. Generally, it is better form to include any given x-value in only one of the pieces of the function. So the equation for the right piece can be y = 3 for x > 3.

4 0

3 years ago

when a stone falls freely, the time taken to hit the ground varies as the square root of the distance fallen. If it takes four s

Eva8 [605]

Answer:

The stone would take approximately 10.107 seconds to fall 500 meters.

Step-by-step explanation:

According to the statement of the problem, the following relationship of direct proportionality is built:

$t \propto y^{1/2}$

$t = k\cdot t^{1/2}$

Where:

$t$ - Time spent by the stone, measured in seconds.

$y$ - Height change experimented by the stone, measured in meters.

$k$ - Proportionality constant, measured in $\frac{s}{m^{1/2}}$ .

First, the proportionality constant is determined by clearing the respective variable and replacing all known variables:

$k = \frac{t}{y^{1/2}}$

If $t = 4\,s$ and $y=78.4\,m$ , then:

$k = \frac{4\,s}{(78.4\,m)^{1/2}}$

$k \approx 0.452\,\frac{s}{m^{1/2}}$

Then, the expression is $t = 0.452\cdot y^{1/2}$ . Finally, if $y = 500\,m$ , then the time is:

$t = 0.452\cdot (500\,m)^{1/2}$

$t \approx 10.107\,s$

The stone would take approximately 10.107 seconds to fall 500 meters.

4 0

3 years ago

A radio station claims that the amount of advertising per hour of broadcast time has an average of 13 minutes and a standard dev

zimovet [89]

Answer:

$Z = 3.33$

Step-by-step explanation:

Z-score:

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.

In this question:

$\mu = 13, \sigma = 1.2$

You listen to the radio station for 1 hour, at a randomly selected time, and carefully observe that the amount of advertising time is equal to 17 minutes. Calculate the z-score for this amount of advertising time.

We have to find Z when X = 17. So

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

$Z = \frac{17 - 13}{1.2}$

$Z = 3.33$

5 0

3 years ago

The slope of the line below is -5. Which of the following is the point slope form of the line (2,-7)

Dominik [7]

Equation of the line in point slope form is y + 7 = -5(x - 2)

Step-by-step explanation:

Step 1: Given slope of the line is -5 and passes through the point (x1, y1) = (2,-7). Equation in point slope form is y - y1 = m(x - x1)

⇒ y - (-7) = -5(x - 2)

⇒ y + 7 = -5(x - 2)

7 0

3 years ago

Dominic has $35.42 in his bank account. He earns $18 for mowing lawns. He spends $1.89 on Gatorade and then deposits the rest in

Pavel [41]

answer

yes he has enough

Step-by-step explanation:

35.42 + 18 -1.89 +35

he has 87.53 this is enough for the skateboard

4 0

3 years ago

Read 2 more answers