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3 years ago

Can I solve i dunno it :)

Mathematics

2 answers:

SVETLANKA909090 [29]3 years ago

5 0

How Long Is The Book?

550 pages.

Its 550 pages, because if you know that he reads 55 pages an hour, then you can multiply the number of pages her reads in an hour by 4 hours. That's 220. Then he will still need 330, just add them together and you will get 550.

How Long Did It Take Naoya to read the entire book?

10 hours.

You know it takes him 4 hours to read 220, and you also know there's 550 pages. And you also know, he can only read 55 pages an hour, so just divide 550 ÷ 55.

MatroZZZ [7]3 years ago

3 0

1. 550 pages left

55×4=220+330=550

2. 10 hours

330÷55=6+4=10

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Kim has 68 spoons, there are 8 boxes of spoons, how many spoons go into each box?

dlinn [17]

8 in each of the first four boxes and 9 in each of the second four boxes

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4 years ago

use the general slicing method to find the volume of The solid whose base is the triangle with vertices (0 comma 0 ), (15 comma

lyudmila [28]

Answer:

volume V of the solid

$\boxed{V=\displaystyle\frac{125\pi}{12}}$

Step-by-step explanation:

The situation is depicted in the picture attached

(see picture)

First, we divide the segment [0, 5] on the X-axis into n equal parts of length 5/n each

[0, 5/n], [5/n, 2(5/n)], [2(5/n), 3(5/n)],..., [(n-1)(5/n), 5]

Now, we slice our solid into n slices.

Each slice is a quarter of cylinder 5/n thick and has a radius of

-k(5/n) + 5 for each k = 1,2,..., n (see picture)

So the volume of each slice is

$\displaystyle\frac{\pi(-k(5/n) + 5 )^2*(5/n)}{4}$

for k=1,2,..., n

We then add up the volumes of all these slices

$\displaystyle\frac{\pi(-(5/n) + 5 )^2*(5/n)}{4}+\displaystyle\frac{\pi(-2(5/n) + 5 )^2*(5/n)}{4}+...+\displaystyle\frac{\pi(-n(5/n) + 5 )^2*(5/n)}{4}$

Notice that the last term of the sum vanishes. After making up the expression a little, we get

$\displaystyle\frac{5\pi}{4n}\left[(-(5/n)+5)^2+(-2(5/n)+5)^2+...+(-(n-1)(5/n)+5)^2\right]=\\\\\displaystyle\frac{5\pi}{4n}\displaystyle\sum_{k=1}^{n-1}(-k(5/n)+5)^2$

But

$\displaystyle\frac{5\pi}{4n}\displaystyle\sum_{k=1}^{n-1}(-k(5/n)+5)^2=\displaystyle\frac{5\pi}{4n}\displaystyle\sum_{k=1}^{n-1}((5/n)^2k^2-(50/n)k+25)=\\\\\displaystyle\frac{5\pi}{4n}\left((5/n)^2\displaystyle\sum_{k=1}^{n-1}k^2-(50/n)\displaystyle\sum_{k=1}^{n-1}k+25(n-1)\right)$

we also know that

$\displaystyle\sum_{k=1}^{n-1}k^2=\displaystyle\frac{n(n-1)(2n-1)}{6}$

and

$\displaystyle\sum_{k=1}^{n-1}k=\displaystyle\frac{n(n-1)}{2}$

so we have, after replacing and simplifying, the sum of the slices equals

$\displaystyle\frac{5\pi}{4n}\left((5/n)^2\displaystyle\sum_{k=1}^{n-1}k^2-(50/n)\displaystyle\sum_{k=1}^{n-1}k+25(n-1)\right)=\\\\=\displaystyle\frac{5\pi}{4n}\left(\displaystyle\frac{25}{n^2}.\displaystyle\frac{n(n-1)(2n-1)}{6}-\displaystyle\frac{50}{n}.\displaystyle\frac{n(n-1)}{2}+25(n-1)\right)=\\\\=\displaystyle\frac{125\pi}{24}.\displaystyle\frac{n(n-1)(2n-1)}{n^3}$

Now we take the limit when n tends to infinite (the slices get thinner and thinner)

$\displaystyle\frac{125\pi}{24}\displaystyle\lim_{n \rightarrow \infty}\displaystyle\frac{n(n-1)(2n-1)}{n^3}=\displaystyle\frac{125\pi}{24}\displaystyle\lim_{n \rightarrow \infty}(2-3/n+1/n^2)=\\\\=\displaystyle\frac{125\pi}{24}.2=\displaystyle\frac{125\pi}{12}$

and the volume V of our solid is

$\boxed{V=\displaystyle\frac{125\pi}{12}}$

3 0

3 years ago

Urgent please help..

Strike441 [17]

Answer:

b = 7√3

Step-by-step explanation:

This 30°- 60°- 90° triangle has the proportions:

side opposite of the 30° angle = x

side opposite of the 60° angle = x√3

side opposite of the 90° angle = 2x

____________________________

Given the side opposite of the 30° angle which is 7 units long, this can be thought of as x. Knowing the proportions of the other sides, we can find b knowing that this is the side opposite of the 60° angle which is x√3.

Since x = 7, x√3 = 7√3, and therefore

b = 7√3.

8 0

3 years ago

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garik1379 [7]

Answer:

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Step-by-step explanation:

did this in 8th grade middle school

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3 years ago

Consider points R, S, and T.

fgiga [73]

Points R, S, and T are coplanar

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3 years ago

Can I solve i dunno it :)​

Can I solve i dunno it :)