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2 years ago

Please look at the screen shot

Mathematics

1 answer:

egoroff_w [7]2 years ago

3 0

Answer:

There are 72 blue marbles, and 8 purple marbles.

Step-by-step explanation:

it's 72 because 9*8=72 and 1*8=8. & 72+8= 80.

i'm not good at explaining.

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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

2 years ago

Jean noticed that the tar pit bubbled more on warm days than on cool days or at night. Is the air temperature the dependent vari

andreev551 [17]

It's indepentent. In fact, the tar pit's temperature DEPENDS (dependent variable) by the air's temperature (independent variable).

6 0

2 years ago

A movie is 2hrs and 4 minutes long. The movie starts at 11:45am. When will the movie end?

dedylja [7]

The movie will end at 1:49 pm.

5 0

2 years ago

Read 2 more answers

8x=4x^2-1 solve by completing the square

Klio2033 [76]

Get the x terms by themselves on one side and a constant on the other side of the equal sign...

4x^2-8x=1 make the leading coefficient equal to one...

x^2-2x=1/4 now halve the linear coefficient, -2 in this case, square it, and add that value to both sides of the equation...-2/2=-1, -1^2=1 so

x^2-2x+1=1+1/4

x^2-2x+1=5/4 now the left side is a perfect square...

(x-1)^2=5/4 take the square root of both sides...

x-1=±√(5/4) add 1 to both sides

x=1±√(5/4)

7 0

3 years ago

Read 2 more answers

Is x=4 a solution to the equation 6=x+2? Is it a solution to the inequality 2x≥9?

jek_recluse [69]

Answer:

Is x = 4 a solution to the equation 6 = x + 2? YES

Is x = 4 a solution to the inequality 2x ≥ 9? NO

Step-by-step explanation:

Is x = 4 a solution to the equation 6 = x + 2? YES

we cans solve the equation 6=x+2 by clearing for x:

6 = x + 2

we move the +2 on the right as a -2 to the left:

6 - 2 = x

4 = x

this way we find that indeed x = 4 is a solution to 6 = x + 2.

Is x = 4 a solution to the inequality 2x ≥ 9? NO

Let's solve the inequality by clearing for x:

2x ≥ 9

we move the 2 that is multiplying on the left to divide on the right side:

x ≥ 9/2

x ≥ 4.5 ⇒ x must be greater than or equal to 4.5

thus, 4 is not a solution to the inequality because 4 is less than 4.5

3 0

3 years ago