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2 years ago

5

Suppose that an insect population’s density, in thousands per acre, during year n, can be modeled by the recursive formula: a1 =

8 an = 2. 9an – 1 – 0. 2(an – 1)2 Which of the following describes what is happening to the insect population for the first five years? The population density decreases each year. The population density increases each year. The population density remains constant. The population alternates between increasing and decreasing.

1 answer:

alexdok [17]2 years ago

4 0

Answer:

D) The population alternates between increasing and decreasing

Step-by-step explanation:

correct on edge

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Diane borrowed 8000 at a rate of 7%, compounded semiannually. Assuming she makes no payments, how much will she owe after 6 year

dmitriy555 [2]

Answer: $12088.55

Step-by-step explanation:

A = p(1+r/n)^nt

A = 8000(1+0.07/2)^2*6

A = 12088.54926

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4 years ago

A 20-year loan of 1000 is repaid with payments at the end of each year. Each of the first ten payments equals 150% of the amount

Alja [10]

Answer:

$x = 97$

Step-by-step explanation:

Given

$t = 20$ --- time (years)

$A =1000$ --- amount

$r = 10\%$ --- rate of interest

Required

The last 10 payments (x)

First, calculate the end of year 1 payment

$y_1(end) = 10\% * 1000 * 150\%$

$y_1(end) = 150$

Amount at end of year 1

$A_1=A - y_1(end) - r * A$

$A_1=1000 - (150 - 10\% * 1000)$

$A_1 =1000 - (150- 100)$

$A_1 =950$

Rewrite as:

$A_1 = 0.95 * 1000^1$

Next, calculate the end of year 1 payment

$y_2(end) = 10\% * 950 * 150\%$

$y_2(end) = 142.5$

Amount at end of year 2

$A_2=A_1 - (y_2(end) - r * A_1)$

$A_2=950 - (142.5 - 10\%*950)$

$A_2 = 902.5$

Rewrite as:

$A_2 = 0.95 * 1000^2$

We have been able to create a pattern:

$A_1 = 1000 * 0.95^1 = 950$

$A_2 = 1000 * 0.95^2 = 902.5$

So, the payment till the end of the 10th year is:

$A_{10} = 1000*0.95^{10}$

$A_{10} = 598.74$

To calculate X (the last 10 payments), we make use of the following geometric series:

$Amount = \sum\limits^{9}_{n=0} x * (1 + r)^n$

$Amount = \sum\limits^{9}_{n=0} x * (1 + 10\%)^n$

$Amount = \sum\limits^{9}_{n=0} x * (1 + 0.10)^n$

$Amount = \sum\limits^{9}_{n=0} x * (1.10)^n$

The amount to be paid is:

$Amount = A_{10}*(1 + r)^{10}$ --- i.e. amount at the end of the 10th year * rate of 10 years

$Amount = 1000 * 0.95^{10} * (1+r)^{10}$

So, we have:

$Amount = \sum\limits^{9}_{n=0} x * (1.10)^n$

$\sum\limits^{9}_{n=0} x * (1.10)^n = 1000 * 0.95^{10} * (1+r)^{10}$

$\sum\limits^{9}_{n=0} x * (1.10)^n = 1000 * 0.95^{10} * (1+10\%)^{10}$

$\sum\limits^{9}_{n=0} x * (1.10)^n = 1000 * 0.95^{10} * (1+0.10)^{10}$

$\sum\limits^{9}_{n=0} x * (1.10)^n = 1000 * 0.95^{10} * (1.10)^{10}$

The geometric sum can be rewritten using the following formula:

$S_n = \sum\limits^{9}_{n=0} x * (1.10)^n$

$S_n =\frac{a(r^n - 1)}{r -1}$

In this case:

$a = x$

$r = 1.10$

$n =10$

So, we have:

$\frac{x(r^{10} - 1)}{r -1} = \sum\limits^{9}_{n=0} x * (1.10)^n$

$\frac{x((1.10)^{10} - 1)}{1.10 -1} = \sum\limits^{9}_{n=0} x * (1.10)^n$

$\frac{x((1.10)^{10} - 1)}{0.10} = \sum\limits^{9}_{n=0} x * (1.10)^n$

$x * \frac{1.10^{10} - 1}{0.10} = \sum\limits^{9}_{n=0} x * (1.10)^n$

So, the equation becomes:

$x * \frac{1.10^{10} - 1}{0.10} = 1000 * 0.95^{10} * (1.10)^{10}$

Solve for x

$x = \frac{1000 * 0.95^{10} * 1.10^{10} * 0.10}{1.10^{10} - 1}$

$x = 97.44$

Approximate

$x = 97$

4 0

3 years ago

Alex73 [517]

Answer:

Solution given:

AD=1.8

AC=3.0

we have

∆ADC is a right angled triangle

Cos A=b/h

<A=cos-¹ (1.8/3)

<A=53.13°

again

∆ABC is a right angled triangle

Tan A=p/b=BC/AC

Tan 53.13×3=BC

BC=4

NOW

Area of triangle =½(AC*BC)=½(4×3)=6 <u>square </u><u>units</u><u> </u><u>is</u><u> </u><u>a</u><u> </u><u>required</u><u> </u><u>area</u><u>.</u>

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3 years ago

Solve for X. Assume that lines which appear tangent are tangent

Reptile [31]

Answer:

C

Step-by-step explanation:

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Answer:

Step-by-step explanation:

I do not know

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