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2 years ago

Sandra is asked to report on the recent increase in popularity of an application based on the number

Mathematics

1 answer:

aalyn [17]2 years ago

3 0

Answer:

Step-by-step explanation:

Report the number of downloads per day. By determining how this number is changing / increasing it will be possible to spot and describe an upward trend if there is one.

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Please help!! I'll give 30 points and brainliest.

Valentin [98]

Step-by-step explanation:

$3 + \frac{9}{4} = \frac{9}{x+4} \\ \\ \therefore \: \frac{3 \times 4 + 9}{4} = \frac{9}{x+4} \\ \\ \therefore \: \frac{12 + 9}{4} = \frac{9}{x+4} \\ \\ \therefore \: \frac{21}{4} = \frac{9}{x+4} \\ \\ \therefore \:21(x + 4) = 36 \\ \\ \therefore \:21x + 84 = 36\\ \\ \therefore \:21x = 36 - 84\\ \\ \therefore \:21x = - 48\\ \\ \therefore \:x = \frac{-48}{21} \\ \\ \therefore \:x = \frac{-16}{7} \\ \\ \huge \red{ \boxed{ \therefore \:x = - 2 \frac{2}{7} }}\\ \\$

8 0

3 years ago

The lengths of pregnancies are normally distributed with a mean of 269269 days and a standard deviation of 1515 days. a. Find th

kati45 [8]

Answer:

a. 0.38%

b. 266.75 days

Step-by-step explanation:

We have the following data, mean (m) 269 and standard deviation (sd) 15, therefore:

a. The first thing is to calculate the number z:

z (x) = (x - m) / sd

z (309) = (309-269) / 15 = 2.67

When looking in the normal distribution table (attached), we have that at this value of z, the probability is:

P (z> 2.67), that is to say we must look in the table -2.67 and this value corresponds to 0.0038, that is to say 0.38%

b. Find the z-value with a left tail of 44%, i.e. 0.44. We look in the table for this value and what value of z corresponds.

invNorm (0.44) = -0.15

Find the corresponding number of days:

x = z * sd + m

we replace

d = -0.15 * 15 + 269 = 266.75 days

7 0

3 years ago

The average July rainfall in a city is 7 inches , but the actual rainfall may vary by as much as 4 inches. What is the range , i

Lady_Fox [76]

The answer is C. (too lazy to explain how sorry)

8 0

2 years ago

Read 2 more answers

e is 150% more than d . what is the ratio d:e in its simplest form? what is the ratio e:d in the form 1::n

Bad White [126]

Answer:

d:e is 2:3

Step-by-step explanation:

if 'e' is 150% more than 'd' we can say that 'e' is 1.5 and 'd' is 1

ratio of 1/1.5 or 1÷3/2 is 2/3

3 0

3 years ago

4x^2 y+8xy'+y=x, y(1)= 9, y'(1)=25

jarptica [38.1K]

Answer with explanation:

$\rightarrow 4x^2y+8x y'+y=x\\\\\rightarrow 8xy'+y(1+4x^2)=x\\\\\rightarrow y'+y\times\frac{1+4x^2}{8x}=\frac{1}{8}$

--------------------------------------------------------Dividing both sides by 8 x

This Integration is of the form ⇒y'+p y=q,which is Linear differential equation.

Integrating Factor

$=e^{\int \frac{1+4x^2}{8x} dx}\\\\e^{\log x^{\frac{1}{8}+\frac{x^2}{2}}\\\\=x^{\frac{1}{8}}\times e^{\frac{x^2}{2}}$

Multiplying both sides by Integrating Factor

$x^{\frac{1}{8}}\times e^{\frac{x^2}{2}}\times [y'+y\times\frac{1+4x^2}{8x}]=\frac{1}{8}\times x^{\frac{1}{8}}\times e^{\frac{x^2}{2}}\\\\ \text{Integrating both sides}\\\\y\times x^{\frac{1}{8}}\times e^{\frac{x^2}{2}}=\frac{1}{8}\int {x^{\frac{1}{8}}\times e^{\frac{x^2}{2}}} \, dx \\\\8y\times x^{\frac{1}{8}}\times e^{\frac{x^2}{2}}=\int {x^{\frac{1}{8}}\times e^{\frac{x^2}{2}}} \, dx\\\\8y\times x^{\frac{1}{8}}\times e^{\frac{x^2}{2}}=-[x^{\frac{9}{8}}]\times\frac{ \Gamma(0.5625, -x^2)}{(-x^2)^{\frac{9}{16}}}\\\\8y\times x^{\frac{1}{8}}\times e^{\frac{x^2}{2}}=(-1)^{\frac{-1}{8}}[ \Gamma(0.5625, -x^2)]+C-----(1)$

When , x=1, gives , y=9.

Evaluate the value of C and substitute in the equation 1.

6 0

3 years ago