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3 years ago

Which one? a) b) c) d)

Mathematics

2 answers:

solniwko [45]3 years ago

8 0

Answer:
d. 3/5

Explanation:
Shaded Area = 15
Total Area = 25

Contact [7]3 years ago

5 0

Answer:

Step-by-step explanation:

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Some friends played a board game. During the game, one unlucky player had to move back 8 spaces 5 turns in a row. Find a number

mojhsa [17]

Answer:

I think that it would be -40

Step-by-step explanation:

I think this because they had to go back 40 spaces because 8 x 5 = 40.

7 0

3 years ago

14a - (2a +9)=2/3 (12a-18)

Dmitrij [34]

Answer: a=-0.75

Step-by-step explanation:

14a - (2a +9)=2/3 (12a-18)

14a - 2a -9=2/3 * 6(2a-3)

12a-9=2*6/3 (2a-3)

12a-9=2*2(2a-3)

12a-9=4(2a-3)

12a-9=8a-12

4a-9=-12

4a=-3

a=-3/4

a=-0.75

3 0

1 year ago

Read 2 more answers

Prove or disprove (from i=0 to n) sum([2i]^4) <= (4n)^4. If true use induction, else give the smallest value of n that it doe

ddd [48]

Answer:

The statement is true for every n between 0 and 77 and it is false for $n\geq 78$

Step-by-step explanation:

First, observe that, for n=0 and n=1 the statement is true:

For n=0: $\sum^{n}_{i=0} (2i)^4=0 \leq 0=(4n)^4$

For n=1: $\sum^{n}_{i=0} (2i)^4=16 \leq 256=(4n)^4$

From this point we will assume that $n\geq 2$

As we can see, $\sum^{n}_{i=0} (2i)^4=\sum^{n}_{i=0} 16i^4=16\sum^{n}_{i=0} i^4$ and $(4n)^4=256n^4$ . Then,

$\sum^{n}_{i=0} (2i)^4 \leq(4n)^4 \iff \sum^{n}_{i=0} i^4 \leq 16n^4$

Now, we will use the formula for the sum of the first 4th powers:

$\sum^{n}_{i=0} i^4=\frac{n^5}{5} +\frac{n^4}{2} +\frac{n^3}{3}-\frac{n}{30}=\frac{6n^5+15n^4+10n^3-n}{30}$

Therefore:

$\sum^{n}_{i=0} i^4 \leq 16n^4 \iff \frac{6n^5+15n^4+10n^3-n}{30} \leq 16n^4 \\\\ \iff 6n^5+10n^3-n \leq 465n^4 \iff 465n^4-6n^5-10n^3+n\geq 0$

and, because $n \geq 0$ ,

$465n^4-6n^5-10n^3+n\geq 0 \iff n(465n^3-6n^4-10n^2+1)\geq 0 \\\iff 465n^3-6n^4-10n^2+1\geq 0 \iff 465n^3-6n^4-10n^2\geq -1\\\iff n^2(465n-6n^2-10)\geq -1$

Observe that, because $n \geq 2$ and is an integer,

$n^2(465n-6n^2-10)\geq -1 \iff 465n-6n^2-10 \geq 0 \iff n(465-6n) \geq 10\\\iff 465-6n \geq 0 \iff n \leq \frac{465}{6}=\frac{155}{2}=77.5$

In concusion, the statement is true if and only if n is a non negative integer such that $n\leq 77$

So, 78 is the smallest value of n that does not satisfy the inequality.

Note: If you compute $(4n)^4- \sum^{n}_{i=0} (2i)^4$ for 77 and 78 you will obtain:

$(4n)^4- \sum^{n}_{i=0} (2i)^4=53810064$

$(4n)^4- \sum^{n}_{i=0} (2i)^4=-61754992$

7 0

3 years ago

A box of cereal states that there are 96 calories in a 3/4

IgorC [24]

Answer:

112 calories per cup

Step-by-step explanation:

Let x = unit rate for calories per cup,

Then (3/4)*x = 84

and x = 84*(4/3) = 112 calories per cup

3 0

2 years ago

Read 2 more answers

Which expressions are equivalent to 3x+3(x+y)?

storchak [24]

Answer: 6x+3y

Step-by-step explanation:

3x+3(x+y)= 3x+3x+3y=6x+3y

6 0

3 years ago