| 2x + 2y = 10<br> y = 5+x

The population, P(t), of China, in billions, can be approximated by1 P(t)=1.394(1.006)t, where t is the number of years since th

vitfil [10]

Answer:

At the start of 2014, the population was growing at 8.34 million people per year.

At the start of 2015, the population was growing at 8.39 million people per year.

Step-by-step explanation:

To find how fast was the population growing at the start of 2014 and at the start of 2015 we need to take the derivative of the function with respect to t.

The derivative shows by how much the function (the population, in this case) is changing when the variable you're deriving with respect to (time) increases one unit (one year).

We know that the population, P(t), of China, in billions, can be approximated by $P(t)=1.394(1.006)^t$

To find the derivative you need to:

$\frac{d}{dt}\left(1.394\cdot \:1.006^t\right)=\\\\\mathrm{Take\:the\:constant\:out}:\quad \left(a\cdot f\right)'=a\cdot f\:'\\\\1.394\frac{d}{dt}\left(1.006^t\right)\\\\\mathrm{Apply\:the\:derivative\:exponent\:rule}:\quad \frac{d}{dx}\left(a^x\right)=a^x\ln \left(a\right)\\\\1.394\cdot \:1.006^t\ln \left(1.006\right)\\\\\frac{d}{dt}\left(1.394\cdot \:1.006^t\right)=(1.394\cdot \ln \left(1.006\right))\cdot 1.006^t$

To find the population growing at the start of 2014 we say t = 0

$P(t)' = (1.394\cdot \ln \left(1.006\right))\cdot 1.006^t\\P(0)' = (1.394\cdot \ln \left(1.006\right))\cdot 1.006^0\\P(0)' = 0.00833901 \:Billion/year$

To find the population growing at the start of 2015 we say t = 1

$P(t)' = (1.394\cdot \ln \left(1.006\right))\cdot 1.006^t\\P(1)' = (1.394\cdot \ln \left(1.006\right))\cdot 1.006^1\\P(1)' = 0.00838904 \:Billion/year$

To convert billion to million you multiple by 1000

$P(0)' = 0.00833901 \:Billion/year \cdot 1000 = 8.34 \:Million/year \\P(1)' = 0.00838904 \:Billion/year \cdot 1000 = 8.39 \:Million/year$

6 0

3 years ago

2. You need to buy grass seed for a new lawn. The lawn will cover a rectangular plot that is 60 feet by 90 feet. Each ounce of g

Mama L [17]

Answer:

45 oz

Step-by-step explanation:

first you need to find the are of the yard. To do that you multiply the length by the width: 60x90=5400 feet

next you divide by 120: 5400/120=45

therefore, you need to buy 45 ounces of grass seed.

6 0

4 years ago

What does x equal in 3.8x = -19

Sauron [17]

Answer: -5

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers

NEED HELP! GIVING OUT BRAINLIEST! (Need long answer)

otez555 [7]

The constant of proportionality is 1.25 and its meaning is the soup price per can
Step-by-step explanation:
The diagram below shows a proportional relationship between the number of cans of soup and the price.
1st:
$3.75 for 3 cans
per can
2nd:
$6.25 for 5 cans
per can
If x is the number of cans and y is the price of x cans, then

This means the constant of proportionality is 1.25 and its meaning is the soup price per can

7 0

2 years ago

Find the area of a rectangle whose length is 15ft and width is 8ft

11Alexandr11 [23.1K]

Answer:

120 ft. sq

Step-by-step explanation:

You use the equation length times width to find the area. 15 x 8 = 120. This equation works for any rectangle

3 0

3 years ago

| 2x + 2y = 10 y = 5+x