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3 years ago

Help me please (photo below)

Mathematics

2 answers:

Julli [10]3 years ago

4 0

His measurements could be as much as 0.1 cm wrong.

He measures 3 cm by 4 cm .

-- The smallest the area could possibly be is if both of his measurements
were too big. The rectangle would actually be 2.9cm by 3.9cm, and the
area would actually be (2.9 x 3.9) = 11.31 square-cm.

-- The biggest the area could possibly be is if both of his measurements
were too small. The rectangle would actually be 3.1 cm by 4.1 cm, and
the area would actually be (3.1 x 4.1) = 12.71 square-cm.

So the true area must be between 11.31 ≤ Area ≤ 12.71 .

Elenna [48]3 years ago

4 0

11.9≤A≤12.1,

I am 80% sure

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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

21 is 84 percent of what number

marysya [2.9K]

Let the required no. be x then according to question
(84/100)*x = 21
x = 21*(100/84)
x = 2100/84
x = 25

hence the required no. is 25

hope it helped

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3 years ago

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Answer:

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3 years ago

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sergiy2304 [10]

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8 0

3 years ago