Prove that Cos4x=8Cosx -8Cosx

2 is the whole number 4 over 5 + 6 is the whole number 14 over 15 and is has to be a fraction

Nonamiya [84]

Answer:

the answer is 9 11/15 or 26/15 in improper fraction form.

7 0

2 years ago

What is 0.08 in 1/10

Paha777 [63]

1/10 of 0.08 is 0.008

4 0

3 years ago

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. What is the total cost of 6 books at N8.50k each?

Sati [7]

Answer:

51

Step-by-step explanation:

1 book= N8.50

therefore 6 books= N8.50 × 6 = N51

8 0

2 years ago

I'm solving systems and I don't understand how to do it pls helpp

kaheart [24]

Answer:

Use the process of elimination. I'll only do one example since you have 4.

Step-by-step explanation:

Let's do the first question.

2x-3y=-11

2x+y=9

Our goal here is to be left with one variable to solve, this way we can use the answer for that variable to find the other. A.K.A only find X to plug into the equation to find Y. To do this, we'll use the process of elimination, in which we need to cancel out a variable.

X seems the easiest here. To cancel 2 (in the top equation), you need to have a -2. And that -2 needs to be the x coefficient in the 2nd equation, in order for us to "cancel" it out. To get -2, you multiply 2 by -1.

-1(2x+y)= -1(9)

Note that whatever you do to one side, you need to do it to both sides! Hence, why I also multiplied 9 by -1. You should now be left with:

-2x -y = -9

Now, we cancel out the positive 2 and -2 from both equations by adding the two equations.

2x-3y= 11

+

-2x-y=-9

X cancels out, so we're left with -4y=-20. Solve for Y, which is 5.

-4y=-20

y=5

Now that you have the Y value, plug it into any of the two equations to find your X value.

2x-3y=11

2x-3(5)=11

2x-15=11

2x=26

x=13

And voilah! Our Y value is 5, and our X value is 13.

It's pretty simple once you understand what's going on. All that we did was to cancel out one variable (either X or Y) in the two equations so that we're left with only one variable to solve. If we cancel out X, we only need to solve for Y. You do this by manipulating one of the two equations (doesn't matter which one). Once you find either X or Y, all you need to is to plug it into one of the original equations. Then, you'll have both X and Y.

And that my friend, is the process of elimination. Good luck!

8 0

2 years ago

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Nitrates are groundwater contaminants derived from fertilizer, septic tank seepage and other sewage. Nitrate poisoning is partic

o-na [289]

Answer:

a) $n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.96})^2}=2401$

And rounded up we have that n=2401

b) $n=\frac{0.07(1-0.07)}{(\frac{0.02}{1.96})^2}=625.22$

And rounded up we have that n=626

And we see that if we have previous info about p the sample size varies a lot.

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

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".

Solution to the problem

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ . And the critical value would be given by:

$z_{\alpha/2}=-1.96, z_{1-\alpha/2}=1.96$

Part a

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And on this case we have that $ME =\pm 0.02$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

Since we don't have prior information about the population proportion we can use ase estimator $\hat p =0.5$ . And replacing into equation (b) the values from part a we got:

$n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.96})^2}=2401$

And rounded up we have that n=2401

Part b

For thi case the estimator for p is $\hat p =0.07$

$n=\frac{0.07(1-0.07)}{(\frac{0.02}{1.96})^2}=625.22$

And rounded up we have that n=626

And we see that if we have previous info about p the sample size varies a lot.

4 0

2 years ago

Prove that Cos4x=8Cosx -8Cosx​

Prove that Cos4x=8Cosx -8Cosx