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3 years ago

Don’t understand how to do this...help would be greatly appreciated:)

Mathematics

1 answer:

tankabanditka [31]3 years ago

7 0

Answer:

You have to substitute the variables

Step-by-step explanation:

For example #3

you will substitute y for 0 and you will substitute x for 2

first equation: 0 = 2-2

second equation: 0=-3(2) +6

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How do you solve 3 = x + 3 + 6x?

joja [24]

Answer:

x=0

Step-by-step explanation:

3 = x + 3 + 6x

Combine like terms

3=7x + 3

Use order of operations to isolate x

3=7x + 3

-3 -3

0/7=7x/7

x=0/7 or 0

4 0

3 years ago

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If a set of data has mean 60 and variance 9 then it's coefficient of variation is

loris [4]

Coefficient of variation is calculated by dividing the standard deviation by the mean multiplied by 100. Given a data set with mean equal to 60 and variance equal to 9, we can calculate the coefficient of variation by finding the value of the standard deviation which is the square root of the variance. so standard deviation is equal to square root of 9 which is 3. Then, the coefficient of variation is equal to 3/60*100 which is equal to 5%.

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3 years ago

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Given sin theta = 1/3 and 0 theta pi/2 find tan 2 theta

Kazeer [188]

Answer:

$\tan2\theta=\pm\dfrac{4\sqrt{2}}{7}$

Step-by-step explanation:

Given: $\sin\theta = \dfrac{1}{3}$

$0\leq \theta \leq \dfrac{\pi}{2}$

Theta lie in first quadrant.

Multiply both sides by 2

$0\leq 2\theta \leq \pi$

2theta lie in I and II quadrant.

$\tan2\theta$ is positive in I and negative in II quadrant.

$\sin\theta=\dfrac{1}{3}$

$\cos\theta=\dfrac{2\sqrt{2}}{3}$

$\sin2\theta=2\sin\theta\cos\theta$

$\sin2\theta=2\cdot \dfrac{1}{3}\cdot \dfrac{2\sqrt{2}}{3}=\dfrac{4\sqrt{2}}{9}$

$\cos2\theta=\pm \sqrt{1-\sin^22\theta}=\pm\dfrac{7}{9}$

$\tan2\theta=\dfrac{\sin2\theta}{\cos2\theta}$

$\tan2\theta=\pm\dfrac{4\sqrt{2}}{7}$

Hence, The value of $\tan2\theta=\pm\dfrac{4\sqrt{2}}{7}$

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JulsSmile [24]

Answer:

Y = 6

X = 10

Step-by-step explanation:

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3 years ago

A study was designed to investigate the effects of two variables, (1) A student's level of mathematical anxiety and (2) teach

Mashcka [7]

Answer:

$P(X>400)=P(\frac{X-\mu}{\sigma}>\frac{400-\mu}{\sigma})=P(Z>\frac{400-440}{20})=P(z>-2)$

And we can find this probability using the complement rule:

$P(z>-2)=1-P(z$

And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.

$P(z>-2)=1-P(z$

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:

$X \sim N(440,20)$

Where $\mu=440$ and $\sigma=20$

We are interested on this probability

$P(X>440)$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\sigma}$

If we apply this formula to our probability we got this:

$P(X>400)=P(\frac{X-\mu}{\sigma}>\frac{400-\mu}{\sigma})=P(Z>\frac{400-440}{20})=P(z>-2)$

And we can find this probability using the complement rule:

$P(z>-2)=1-P(z$

And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.

$P(z>-2)=1-P(z$

6 0

3 years ago