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3 years ago

Evaluate each expression 3/4+2/5

Mathematics

2 answers:

Norma-Jean [14]3 years ago

7 0

Answer: 3/4 ×5 + 2/5 ×4

15/20 + 8/20 = 23/20 = 1 3/20 or 1.15

Step-by-step explanation:

Evgen [1.6K]3 years ago

3 0

Answer: 1 and 3/20

Step-by-step explanation:

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Which of the following is an arithmetic sequence?

laiz [17]

Answer:

0,2,4,6

Step-by-step explanation:

This sequence is arithmetic because the same number is being added each time: 2. With the others, the number being added changes every time.

5 0

3 years ago

Read 2 more answers

I'll give you brainliest if you answer correctly! <3

NeTakaya

Answer:

The answer should the second Arrow option.

Step-by-step explanation:

I'm not into this subject well so, <em>so sorry if its wrong</em>..

This type of test is in K12 which is my school.

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2 years ago

Need some help with this question please

Serggg [28]

Answer:

$\frac{15}{17}$

Step-by-step explanation:

$\cos( \alpha ) = \frac{ad}{hip} \\ \\ \sin( \alpha ) = \frac{op}{hip}$

Pythagorean theorem

hip² = op² + ad²

17² = x² + 8²

x² = 17² - 8²

$x \: = \sqrt{{17}^{2} - {8}^{2} } \\ x = \sqrt{289 - 64} \\ x = \sqrt{225} \\ x = 15$

$\sin( \alpha ) = - \frac{15}{17}$

$\sin( - \alpha ) = \frac{15}{17}$

4 0

3 years ago

Scott is on his school's academic team. On average, it takes Scott 4 minutes, with a standard deviation of 0.25 minutes, to solv

uysha [10]

Answer:

15.87% is the chance that Scott takes more than 4.25 minutes to solve a problem at an academic bowl.

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 4 minutes

Standard Deviation, σ = 0.25 minutes

We standardize the given data.

Formula:

$z_{score} = \displaystyle\frac{x-\mu}{\sigma}$

P(more than 4.25 minutes to solve a problem)

$P( x > 4.25) = P( z > \displaystyle\frac{4.25 - 4}{0.25}) = P(z > 1)$

$= 1 - P(z \leq 1)$

Calculation the value from standard normal z table, we have,

$P(x > 4.25) = 1 - 0.8413 = 0.1587 = 15.87\%$

Thus,15.87% is the chance that Scott takes more than 4.25 minutes to solve a problem at an academic bowl.

8 0

3 years ago

Which of the following is not one of the 8th roots of unity?

Anika [276]

Answer:

1+i

Step-by-step explanation:

To find the 8th roots of unity, you have to find the trigonometric form of unity.

1. Since $z=1=1+0\cdot i,$ then

$Rez=1,\\ \\Im z=0$

and

$|z|=\sqrt{1^2+0^2}=1,\\ \\\\\cos\varphi =\dfrac{Rez}{|z|}=\dfrac{1}{1}=1,\\ \\\sin\varphi =\dfrac{Imz}{|z|}=\dfrac{0}{1}=0.$

This gives you $\varphi=0.$

Thus,

$z=1\cdot(\cos 0+i\sin 0).$

2. The 8th roots can be calculated using following formula:

$\sqrt[8]{z}=\{\sqrt[8]{|z|} (\cos\dfrac{\varphi+2\pi k}{8}+i\sin \dfrac{\varphi+2\pi k}{8}), k=0,\ 1,\dots,7\}.$

Now

at k=0, $z_0=\sqrt[8]{1} (\cos\dfrac{0+2\pi \cdot 0}{8}+i\sin \dfrac{0+2\pi \cdot 0}{8})=1\cdot (1+0\cdot i)=1;$

at k=1, $z_1=\sqrt[8]{1} (\cos\dfrac{0+2\pi \cdot 1}{8}+i\sin \dfrac{0+2\pi \cdot 1}{8})=1\cdot (\dfrac{\sqrt{2}}{2}+i\dfrac{\sqrt{2}}{2})=\dfrac{\sqrt{2}}{2}+i\dfrac{\sqrt{2}}{2};$

at k=2, $z_2=\sqrt[8]{1} (\cos\dfrac{0+2\pi \cdot 2}{8}+i\sin \dfrac{0+2\pi \cdot 2}{8})=1\cdot (0+1\cdot i)=i;$

at k=3, $z_3=\sqrt[8]{1} (\cos\dfrac{0+2\pi \cdot 3}{8}+i\sin \dfrac{0+2\pi \cdot 3}{8})=1\cdot (-\dfrac{\sqrt{2}}{2}+i\dfrac{\sqrt{2}}{2})=-\dfrac{\sqrt{2}}{2}+i\dfrac{\sqrt{2}}{2};$

at k=4, $z_4=\sqrt[8]{1} (\cos\dfrac{0+2\pi \cdot 4}{8}+i\sin \dfrac{0+2\pi \cdot 4}{8})=1\cdot (-1+0\cdot i)=-1;$

at k=5, $z_5=\sqrt[8]{1} (\cos\dfrac{0+2\pi \cdot 5}{8}+i\sin \dfrac{0+2\pi \cdot 5}{8})=1\cdot (-\dfrac{\sqrt{2}}{2}-i\dfrac{\sqrt{2}}{2})=-\dfrac{\sqrt{2}}{2}-i\dfrac{\sqrt{2}}{2};$

at k=6, $z_6=\sqrt[8]{1} (\cos\dfrac{0+2\pi \cdot 6}{8}+i\sin \dfrac{0+2\pi \cdot 6}{8})=1\cdot (0-1\cdot i)=-i;$

at k=7, $z_7=\sqrt[8]{1} (\cos\dfrac{0+2\pi \cdot 7}{8}+i\sin \dfrac{0+2\pi \cdot 7}{8})=1\cdot (\dfrac{\sqrt{2}}{2}-i\dfrac{\sqrt{2}}{2})=\dfrac{\sqrt{2}}{2}-i\dfrac{\sqrt{2}}{2};$

The 8th roots are

$\{1,\ \dfrac{\sqrt{2}}{2}+i\dfrac{\sqrt{2}}{2},\ i, -\dfrac{\sqrt{2}}{2}+i\dfrac{\sqrt{2}}{2},\ -1, -\dfrac{\sqrt{2}}{2}-i\dfrac{\sqrt{2}}{2},\ -i,\ \dfrac{\sqrt{2}}{2}-i\dfrac{\sqrt{2}}{2}\}.$

Option C is icncorrect.

5 0

3 years ago