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2 years ago

Help please it for a really important test

Mathematics

1 answer:

Arada [10]2 years ago

4 0

Answer:

cant tell you the answer but i can tell you the person that messed up isn't that good at math

Step-by-step explanation:

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) The density of oil in a circular oil slick on the surface of the ocean at a distance of r meters from the center of the slick

Feliz [49]

Answer:

Therefore the mass of the of the oil is 409.59 kg.

Step-by-step explanation:

Let us consider a circular disk. The inner radius of the disk be r and the outer diameter of the disk be (r+Δr).

The area of the disk

=The area of the outer circle - The area of the inner circle

= $\pi (r+\triangle r)^2- \pi r^2$

$=\pi [r^2+2r\triangle r+(\triangle r)^2-r^2]$

$=\pi [2r\triangle r+(\triangle r)^2]$

Since (Δr)² is very small, So it is ignorable.

∴ $A=2\pi r\triangle r$

The density $\delta (r)= \frac{40}{1+r^2}$

We know,

Mass= Area× density

$=(2r \pi \triangle r)(\frac{40}{1+r^2}})$

Total mass $M=\sum_{i=1}^n \frac{80r_i\pi }{1+r^2}\triangle r_i$

Therefore

$\sum_{i=1}^n \frac{80r_i\pi }{1+r^2}\triangle r_i=\int_0^5 \frac{80r\pi }{1+r^2}dr$

$=40\pi[ln(1+r^2)]_0^5$

$=40\pi [ln(1+5^2)-ln(1+0^2)]$

$=40\pi ln(26)$

= 409.59 kg (approx)

Therefore the mass of the of the oil is 409.59 kg.

3 0

2 years ago

Isaiah has $7.15 in Dimes and Nickels. He has a total of 91 coins. How many of each coin does he have? Group of answer choices d

yarga [219]

Answer:

Dimes = x = 52

Nickels = y = 39

Step-by-step explanation:

Let

Dimes = x

Nickels = y

x + y = 91 (1)

0.10x + 0.05y = 7.15 (2)

From (1)

x = 91 - y

Substitute x = 91 - y into (2)

0.10x + 0.05y = 7.15

0.10(91 - y) + 0.05y = 7.15

9.10 - 0.10y + 0.05y = 7.15

- 0.10y + 0.05y = 7.15 - 9.10

-0.05y = -1.95

y = -1.95 / 0.05

= 39

Substitute y = 39 into (1)

x + y = 91

x + 39 = 91

x = 91 - 39

x = 52

Dimes = x = 52

Nickels = y = 39

7 0

3 years ago

What is the 200 hundredth digit in 5/6

sladkih [1.3K]

5/6 = .83333333(repeating)

the 200th digit is 3

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3 years ago

Brennan is planting seeds. He has 1/5 of a pack of seeds and 5 flower pots. What fraction of a pack of seeds will be planted in

Maru [420]

(1/5)/(5)=(1/5)(1/5)=1/25 of a pack of seeds will be planted in each pot

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2 years ago

You are building a rectangular dog pen with an area of 90ft^2. You want the length to be 3 ft longer that twice it's width. What

Alecsey [184]

I think the answers is the you think is if you think okayω

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3 years ago