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4 years ago

I need answers to these 3 questions please asap!!

Mathematics

1 answer:

Tatiana [17]4 years ago

8 0

1) 8
2) 9
3) 9
If you need the work lmk:)

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a teacher is experimenting with computer- based instruction. In which situation could the teacher use a hypothesis test for a di

Ilia_Sergeevich [38]

Answer:

(i) She gives each student a pretest. Then she teaches a lesson using a computer program. Afterwards, she gives each student a posttest. The teacher wants to see if the difference in scores will show an improvement.

Step-by- Step

The situation is a case of matched or paired samples since the samples are dependent. The two measurements are drawn from the same pair of individuals The parameter that is tested using matched pairs is the population mean and this is what teacher intends to use a hypothesis test for.

8 0

3 years ago

4. Using the geometric sum formulas, evaluate each of the following sums and express your answer in Cartesian form.

nikitadnepr [17]

Answer:

$\sum_{n=0}^9cos(\frac{\pi n}{2})=1$

$\sum_{k=0}^{N-1}e^{\frac{i2\pi kk}{2}}=0$

$\sum_{n=0}^\infty (\frac{1}{2})^n cos(\frac{\pi n}{2})=\frac{1}{2}$

Step-by-step explanation:

$\sum_{n=0}^9cos(\frac{\pi n}{2})=\frac{1}{2}(\sum_{n=0}^9 (e^{\frac{i\pi n}{2}}+ e^{\frac{i\pi n}{2}}))$

$=\frac{1}{2}(\frac{1-e^{\frac{10i\pi}{2}}}{1-e^{\frac{i\pi}{2}}}+\frac{1-e^{-\frac{10i\pi}{2}}}{1-e^{-\frac{i\pi}{2}}})$

$=\frac{1}{2}(\frac{1+1}{1-i}+\frac{1+1}{1+i})=1$

2nd

$\sum_{k=0}^{N-1}e^{\frac{i2\pi kk}{2}}=\frac{1-e^{\frac{i2\pi N}{N}}}{1-e^{\frac{i2\pi}{N}}}$

$=\frac{1-1}{1-e^{\frac{i2\pi}{N}}}=0$

3th

$\sum_{n=0}^\infty (\frac{1}{2})^n cos(\frac{\pi n}{2})==\frac{1}{2}(\sum_{n=0}^\infty ((\frac{e^{\frac{i\pi n}{2}}}{2})^n+ (\frac{e^{-\frac{i\pi n}{2}}}{2})^n))$

$=\frac{1}{2}(\frac{1-0}{1-i}+\frac{1-0}{1+i})=\frac{1}{2}$

What we use?

We use that

$e^{i\pi n}=cos(\pi n)+i sin(\pi n)$

and

$\sum_{n=0}^k r^k=\frac{1-r^{k+1}}{1-r}$

6 0

4 years ago

2(2x + 3) = -6(x + 9)

sergeinik [125]

Answer:

Your answer is -6.

Step-by-step explanation:

Simplify 2(2x+3) to get 4x+6

Then simplify -6(x+9) to get -6x-54

Now you have 4x+6=-6x-54

Move all of the coefficients to one side:

10x+6=-54

Move all of the constants to the other side:

10x=-60

Divide each side by 10:

10/10x=-60/10

To get your answer of -6.

6 0

3 years ago

The cost of 12 pencils is rupees 37 4 by 5 find the cost of one pencil

Svetllana [295]

Answer:

Cost of 12 pencils = 37 4/5 = 189/5

Cost of 1 pencil = 189/5 ÷ 12

= 189/5 x 1/12 = 189/60 = 63/20 = 3 3/20

So required answer is 3 3/20

Hope This Helps You!

5 0

3 years ago

Show all work <br> Find exact value of x

Illusion [34]

Answer:

129 is x

Step-by-step explanation:

Your equation would be like this x= 45 + 6=180 (180 because the sum of the angle measures in a triangle is 180 always)

so once you add 45+6 =51 the equation is now x=51=180 so you subtract 51 from both sides so it equals as this x=51=180

x =-51= -51

x= 129

5 0

3 years ago