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3 years ago

What is the sum of the first 39 positive odd numbers?

1 answer:

7 0

1-39 ODD:
1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37,39
Now you'd add them all up.
1+3+5+7+9 = 25
11+13+15+17+19 = 75
21+23+25+27+29 = 125
31+33+35+37+39 = 175
Add the totals:
25+75+125+175
The answer would be 400.

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Pearson realize help please!

yulyashka [42]

Answer:

I think it would be 15

Step-by-step explanation:

Because if you split the number line into 6 different sections (with the 15 on the left side and the 16 on the right side) and shade/fill in 2 of those, you would be closer to 15.

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2 years ago

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gogolik [260]

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3 years ago

Solve the following recurrence relation: <br> <img src="https://tex.z-dn.net/?f=A_%7Bn%7D%3Da_%7Bn-1%7D%2Bn%3B%20a_%7B1%7D%20%3D

-Dominant- [34]

By iteratively substituting, we have

$a_n = a_{n-1} + n$

$a_{n-1} = a_{n-2} + (n - 1) \implies a_n = a_{n-2} + n + (n - 1)$

$a_{n-2} = a_{n-3} + (n - 2) \implies a_n = a_{n-3} + n + (n - 1) + (n - 2)$

and the pattern continues down to the first term $a_1=0$ ,

$a_n = a_{n - (n - 1)} + n + (n - 1) + (n - 2) + \cdots + (n - (n - 2))$

$\implies a_n = a_1 + \displaystyle \sum_{k=0}^{n-2} (n - k)$

$\implies a_n = \displaystyle n \sum_{k=0}^{n-2} 1 - \sum_{k=0}^{n-2} k$

Recall the formulas

$\displaystyle \sum_{n=1}^N 1 = N$

$\displaystyle \sum_{n=1}^N n = \frac{N(N+1)}2$

It follows that

$a_n = n (n - 2) - \dfrac{(n-2)(n-1)}2$

$\implies a_n = \dfrac12 n^2 + \dfrac12 n - 1$

$\implies \boxed{a_n = \dfrac{(n+2)(n-1)}2}$

4 0

2 years ago

In art class,Kerion is coloring a pattern where half of the squares on her paper are being colored blue. Of the blue squares,1/3

kolbaska11 [484]

100% of Kerion's paper squares are:
(100% / 100%) = 1
Half of the squares of your paper are colored blue:
(1) / (2) = 1/2
Of the blue squares, 1/3 of them will also have stripes:
(1/2) * (1/3) = 1/6
answer
A fraction of (1/6) squares will be blue with strips

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3 years ago

According to Newton’s third law, for every action, there is an equal and opposite

Furkat [3]

True? I dont know what you're trying to ask. if you're asking whether or not it's true, it is.

5 0

3 years ago

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