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Bezzdna [24]
3 years ago
6

How do you know pi x r x r x h

Mathematics
1 answer:
Nat2105 [25]3 years ago
4 0
V= πr^2h

This is the formula for volume of a cylinder. The volume formula builds off the area formula. Where area is more 2-dimensional, volume is 3-dimensional. You can think of a flat sheet of paper for area (2-dimensional) and a solid box for volume (3-dimensional).

Usually your teacher would give the formulas when starting this section of math. From there, either keep a list of needed formulas in your math folder for easy reference, or try to memorize the formulas for the current section of math you are working on. Some teachers allow formula reference sheets and some do not.

Hope this answers your question! :)
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The change in water vapor in a cloud is modeled by a polynomial function, C(x). C(x) = x^3+ 5x^2+3x+30 Describe how to find the
kari74 [83]

Answer:

Suppose the equation that describes the change in water vapor in a cloud (y) with respect to temperature (x): C(x) = x³ - 4x² - 7x + 10

You find the x-intercepts of the cubic equation by finding the roots. Let y be zero:

x³ - 4x² - 7x + 10 = 0

Now, find possible factors of the constant term in the equation: 10. These could be 1, 2, 5, and 10. Suppose we choose 1. We substitute x=1. If the answer is zero, then x=1 is one of the roots.

(1)³ - 4(1)² - 7(1) + 10 = 0

Hence, x=1 or x-1 = 0 is one of the roots. We use this to manipulate the rest of the terms in the original equation, such that you can factor out (x-1). Substitute -x² - 3x² to -4x³ because they are just equal. Same is true for +3x - 10x for -7x:

x³ -x² - 3x²+3x - 10x + 10 = 0

Factor out like terms such that they have a common factor of (x-1) as much as possible.

x³ -x² = x²(x-1)

- 3x²+3x = -3x(x-1)

- 10x + 10 = -10(x-1)

The factored equation is:

x²(x-1)-3x(x-1)-10(x-1) = 0

Factor out (x-1):

(x-1)(x²-3x-10) = 0

Now, we have the quadratic equation left to be solved:x²-3x-10

Use the quadratic formula to find the roots:

x = [-b +/- √(b²-4ac)]/2a,

The a, b and c coefficients are based on the general form of the quadratic equation: ax² + bx + c. Hence, a=1, b=-3 and c=-10. Substituting the values:

x = [-(-3) +/- √((-3)²-4(1)(-10))]/2(1)

x = 5, -2

Therefore, the roots of the cubic equations are x = 1, x = 5 and x =- 2. These are the x-intercepts of the equation. At temperatures °C, 5°C and -2°C, there is no change in water vapor in a cloud. The graph is shown in the attached picture

Step-by-step explanation:

7 0
2 years ago
What’s the answer for this question?
qaws [65]

Answer:

d.

Step-by-step explanation:

you would put 4 in the x places and 2 in the yplaces and then you would distribute 4^2 +3(2)/4(2)

16+6/2=22/8=2 3/4

8 0
3 years ago
Help please. thank you
tatyana61 [14]
I think it D cause 30(cos(30x)+14=-16
Your dividing by 30
your 180 (which is degrees) is
radians. As the cosine function is periodic with period 2 we get

6 0
3 years ago
Read 2 more answers
Someone help me with this table !!!!!!!
Artemon [7]

Answer:  The image of the completed table is shown below

In the completed table, we have the following values (left to right)

  • Row One: 30, 10, 40
  • Row Two: 15, 45, 60
  • Row Three: 45, 55, 100

==============================================

Explanation:

We're told that "40 people responded that they use mouthwash". That means we'll write "40" at the very end of the "use mouthwash" row. This represents the total number of people who use mouthwash, since we're underneath the "total" in that far right column.

Then we're further told that "Of the people who use mouthwash, 30 people use floss", so we'll write "30" in the first row, first column blank space. These are the people who both floss and use mouthwash. Because earlier we know 40 people use mouthwash overall, this leaves 40-30 = 10 people who use mouthwash, but they don't floss.

To summarize so far: In row 1, we have the following values from left to right: 30, 10, 40

The first two items of this row must add to the last item.

---------------------

Now onto row 2

Since 40 people use mouthwash, and 100 people were surveyed, this means that 100-40 = 60 people do not use mouthwash.  The value 60 goes at the very end of row 2. This represents another total.

Like earlier, the first two items must add to the last. So 40+60 = 100.

Now turn to the fact that "45 people responded that they don't floss and don't use mouthwash". This tells us that "45" will be in the "no mouthwash" row and "don't floss" column.

We have 60 people who don't use mouthwash, and 45 of those people also don't floss. Therefore, 60-45 = 15 people do floss but they don't use mouthwash. We'll write "15" in the second row, first column.

Along row 2, we have the following values: 15, 45, 60

----------------------

Row 3

For each column, add up the first two items to get the third one. This will lead to the totals along this bottom row.

  • Floss: 30+15 = 45
  • Don't Floss: 10+45 = 55 .... note how this matches up with the third piece of information your teacher provided

The third column is already done, but again we can see that 40+60 = 100.

Furthermore, the first two items of the third row add to 45+55 = 100 which helps confirm our answers.

The full completed table is shown below.

------------------------

To summarize, we are effectively just sorting the values given to us to write them into the table. Then we use a bit of algebraic detective work to find out what values are missing so we fill out the completed table.

7 0
2 years ago
What is the square root of 25<br><br>a.4<br>b.21<br>c.10<br>d.1​
photoshop1234 [79]

the square root of 25 is 5

5x5=25

5 0
3 years ago
Read 2 more answers
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