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3 years ago

What is a formula for the nth term of the given sequence? 48, 72, 108

Mathematics

1 answer:

WITCHER [35]3 years ago

7 0

Answer:

$a_n=48*1.5^{n-1}$

Step-by-step explanation:

<u>Geometric Sequence</u>

In geometric sequences, each term is found by multiplying (or dividing) the previous term by a fixed number, called the common ratio.

We are given the sequence:

48, 72, 108, ...

The common ratio is found by dividing the second term by the first term:

$r=\frac{72}{48}=1.5$

To ensure this is a geometric sequence, we use the ratio just calculated to find the third term a3=72*1.5=108.

Now we are sure this is a geometric sequence, we use the general term formula:

$a_n=a_1*r^{n-1}$

Where a1=48 and r=1.5

$\boxed{a_n=48*1.5^{n-1}}$

For example, to find the 5th term:

$a_5=48*1.5^{5-1}=48*1.5^{4}=243$

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Suppose that in a random sample of size 200, standard deviation of the sampling distribution of the sample mean 0.08. researcher

sertanlavr [38]

Answer:

400

Step-by-step explanation:

The computation of the sample size needed is shown below:

Since at the sample size of 200 there is a standard deviation of 0.08

But when the standard deviation is 0.04 so the sample size is 400

As sample standard deviation would be inversely proportional to the square root of the sample size

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3 years ago

Which function is the same as y = 3 cosine (2 (x startfraction pi over 2 endfraction)) minus 2? y = 3 sine (2 (x startfraction p

kirza4 [7]

The function which is same as the function y = 3cos(2(x +π/2)) -2 is: Option A: y= 3sin(2(x + π/4)) - 2

<h3>How to convert sine of an angle to some angle of cosine?</h3>

We can use the fact that:

$\sin(\theta) = \cos(\pi/2 - \theta)\\\sin(\theta + \pi/2) = -\cos(\theta)\\\cos(\theta + \pi/2) = \sin(\theta)$

to convert the sine to cosine.

<h3>Which trigonometric functions are positive in which quadrant?</h3>

In first quadrant (0 < θ < π/2), all six trigonometric functions are positive.
In second quadrant(π/2 < θ < π), only sin and cosec are positive.
In the third quadrant (π < θ < 3π/2), only tangent and cotangent are positive.
In fourth (3π/2 < θ < 2π = 0), only cos and sec are positive.

(this all positive negative refers to the fact that if you use given angle as input to these functions, then what sign will these functions will evaluate based on in which quadrant does the given angle lies.)

Here, the given function is:

$y= 3\cos(2(x + \pi/2)) - 2$

The options are:

$y= 3\sin(2(x + \pi/4)) - 2$
$y= -3\sin(2(x + \pi/4)) - 2$
$y= 3\cos(2(x + \pi/4)) - 2$
$y= -3\cos(2(x + \pi/2)) - 2$

Checking all the options one by one:

Option 1: $y= 3\sin(2(x + \pi/4)) - 2$

$y= 3\sin(2(x + \pi/4)) - 2\\y= 3\sin (2x + \pi/2) -2\\y = -3\cos(2x) -2\\y = 3\cos(2x + \pi) -2\\y = 3\cos(2(x+ \pi/2)) -2$

(the last second step was the use of the fact that cos flips its sign after pi radian increment in its input)
Thus, this option is same as the given function.

Option 2: $y= -3\sin(2(x + \pi/4)) - 2$

This option if would be true, then from option 1 and this option, we'd get:
$-3\sin(2(x + \pi/4)) - 2= -3\sin(2(x + \pi/4)) - 2\\2(3\sin(2(x + \pi/4))) = 0\\\sin(2(x + \pi/4) = 0$

which isn't true for all values of x.

Thus, this option is not same as the given function.

Option 3: $y= 3\cos(2(x + \pi/4)) - 2$

The given function is $y= 3\cos(2(x + \pi/2)) - 2 = 3\cos(2x + \pi) -2 = -3\cos(2x) -2$

This option's function simplifies as:

$y= 3\cos(2(x + \pi/4)) - 2 = 3\cos(2x + \pi/2) -2 = -3\sin(2x) - 2$

Thus, this option isn't true since $\sin(2x) \neq \cos(2x)$ always (they are equal for some values of x but not for all).

Option 4: $y= -3\cos(2(x + \pi/2)) - 2$

The given function simplifies to: $y= 3\cos(2(x + \pi/2)) - 2 = 3\cos(2x + \pi) -2 = -3\cos(2x) -2$

The given option simplifies to:

$y= -3\cos(2(x + \pi/2)) - 2 = -3\cos(2x + \pi ) -2\\y = 3\cos(2x) -2$

Thus, this function is not same as the given function.

Thus, the function which is same as the function y = 3cos(2(x +π/2)) -2 is: Option A: y= 3sin(2(x + π/4)) - 2

Learn more about sine to cosine conversion here:

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2 years ago

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Tom [10]

Answer: 72

Step-by-step explanation:

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3 years ago

A large cheese pizza costs $7.50. Each additional topping for the pizza costs $1.35. If the total bill for the pizza Sally order

konstantin123 [22]

Answer: She ordered 4 toppings.

Step-by-step explanation:

Given: Total cost of pizza = $ 12.90

Cost of pizza =$7.50

Price per topping = $1.35

Let x = Number of toppings,

Total cost of pizza = (Cost of pizza) + (price per topping) × (Number of topping)

$12.90= 7.50+1.35x\\\\\Rightarrow\ 1.35x=12.90-7.50\\\\\Rightarrow\ 1.35x=5.4\\\\\Rightarrow\ x=\dfrac{5.4}{1.35}\\\\\Rightarrow\ x=\dfrac{540}{135}=4$

hence, she ordered 4 toppings.

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3 years ago

Mrs. Cruise prepared gift baskets for her friend. She had 21 mangoes 20 apples and 14 avocados. She places the fruits in each ba

GarryVolchara [31]

Answer:

Step-by-step explanation:

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3 years ago

What is a formula for the nth term of the given sequence? 48, 72, 108​

What is a formula for the nth term of the given sequence? 48, 72, 108