Solve for x. She<br> - 7/2x+ 1/2= 31/6

Write out the first few terms of the series Summation from n equals 0 to infinity (StartFraction 2 Over 3 Superscript n EndFract

anyanavicka [17]

Answer:

$\sum\limits_{n=0}^{\infty} \frac{2}{3^n}\frac{(-1)^n}{5^n} = 15/8$

Step-by-step explanation:

The sum you are trying to understand is this.

$\sum\limits_{n=0}^{\infty} \frac{2}{3^n}\frac{(-1)^n}{5^n}$

Remember that in general when you have a geometric series

$\sum\limits_{n = 0}^{\infty} a*r^n$ you have that

$\sum\limits_{n = 0}^{\infty} a*r^n = \frac{a}{1-r}$ and that equality is true as long as $|r| < 1$ .

Therefore here we have

$\sum\limits_{n=0}^{\infty} \frac{2}{3^n}\frac{(-1)^n}{5^n} = \sum\limits_{n=0}^{\infty} 2* \big(\frac{-1}{3*5} \big)^n = \sum\limits_{n=0}^{\infty} 2* \big(\frac{-1}{15} \big)^n$ and $\big|\frac{-1}{15} \big| = \frac{1}{15} < 1$

Therefore we can use the formula and

$\sum\limits_{n=0}^{\infty} 2* \big(\frac{-1}{15} \big)^n = \frac{2}{1-(-1/15)} = \frac{2}{1+1/15} = 30/16 = 15/8$

5 0

3 years ago

Identify the outlier in the data set 6, 9, 3, 2, 10, 138, 13. Then, find the mean with and without the outlier. If necessary, ro

Andrews [41]

138 is the outlier since it is more than 1.5 * IQR past the third quartile of the data set.

With this upper outlier, the mean will be significantly higher. Without it, it will lower back down, so B is your answer

5 0

3 years ago

A dress regularly sells for $96. The sale price is $68. Find the percent decrease of the sale price from the regular price. Roun

yuradex [85]

Answer:

29.2 percent decrease

Step-by-step explanation:

the difference between 96 and 68 is 28 bucks

28 is what percent of 96

is over of

x/100 x 28/96

cross multiply=2800/96

divide 2800 by 96 and the answer is 29.1666

4 0

3 years ago

You and your brother are reading the same novel. You want to get ahead of him in the book, so you decide to read 303030 minutes

aliina [53]

Answer:

For this case we have the following notation:

y= the number of minutes that you read

x = the number of minutes that your brother read

And we have that you decide to read 30 minutes longer than your brother, so the equation would be:

y = x+30

And for the other part of the question if x =15 we got:

y = 15+30 = 45

Step-by-step explanation:

Assuming this complete question: "You and your brother are reading the same novel. You want to get ahead of him in the book, so you decide to read 30 minutes longer than your brother reads. Write an equation for the number of minutes you read, y, when your brother reads x number of minutes.

How many minutes will you read if your brother reads for 15 minutes?"

Solution to the problem

For this case we have the following notation:

y= the number of minutes that you read

x = the number of minutes that your brother read

And we have that you decide to read 30 minutes longer than your brother, so the equation would be:

y = x+30

And for the other part of the question if x =15 we got:

y = 15+30 = 45

5 0

4 years ago

Sarah has 284 coins in a piggy bank with a total value of $22.78. Sarah has 173 pennies, 5 more dimes than nickels, the rest are

pickupchik [31]

Let P = number of coins of pennies (1 penny = 1 cent)
Let N = number of coins of nickels (1 nickel = 5 cents)
Let D = number of coins of dimes (1 dime = 10 cents)
Let Q = number of coins of quarters (1 quarter = 25 cents)

a) P + N + D + Q = 284 coins, but P = 173 coins, then:
173 + N + D + Q =284 coins
(1) N + D + Q = 111 coins

b) D = N + 5 OR D - N =5 coins
(2) D - N = 5 coins

c) Let's find the VALUE in CENTS of (1) that is N + D + Q = 111 coins
5N + 10D + 25 Q = 2,278 - 173 (1 PENNY)
(3) 5N + 10D + 25Q = 2105 cents
Now we have 3 equation with 3 variables:

(1) N + D + Q = 111 coins
(2) D - N = 5 coins
(3) 5N + 10D + 25Q = 2105 cents
Solving it gives:
17 coins N ( x 5 = 85 cents)
22 coins D ( x 10 = 220 cents)
72 coins D ( x 25 = 1,800 cents)
and 173 P,
proof:
that makes a total of 85+2201800+172 =2,278 c or $22.78

7 0

3 years ago

Solve for x. She - 7/2x+ 1/2= 31/6