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3 years ago

Complete the identity. cos (alpha - beta)/cos alpha cos beta = ?

2 answers:

5 0

$\frac{cos(a-b)}{cos(a)cos(b)} = \frac{cos(a)cos(b)+sin(a)sin(b)}{cos(a)cos(b)} = 1+ \frac{sin(a)sin(b)}{cos(a)cos(b)} =1+tan(a)tan(b)$

Note that I used these identities : $cos(a-b)=cos(a)cos(b)+sin(a)sin(b)$ and $tan(a)= \frac{sin(a)}{cos(a)}$

MrRa [10]3 years ago

3 0

I belive the answer to be b

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Common factors for 15 and 27

ivanzaharov [21]

Its 3. Because 5*3 is 15 and 9*3 is 27

3 0

4 years ago

2/5 + 3/8 - Adding fractions

m_a_m_a [10]

Answer:31/40

Step-by-step explanation:

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3 years ago

Read 2 more answers

The initial value of a stock is $2500. The value of the stock is expected to grow at an annual rate of 4%. Let x represent the n

vekshin1

Answer:

y = ($2500)(1.04)^x

Step-by-step explanation:

The initial value = $2500

The value of the stock is expected to grow at the rate of 4%

Let x represent the number of years since the stock was made available for purchase.

Let y represent the value of the stock x years later.

y1 = amount of money after one year.

y1 = $2500 (100% + 4%)

y1 = $2500 (104%)

y1 = $2500(1.04)

y2 = amount of money after two years

y2 = y1 (100% + 4%)

y2 = y1 (104%)

y2 = y1(1.04)

y2 = $2500(1.04)(1.04)

y2 = $2500(1.04)^2

This will give a pattern

y5 = $2500(1.04)^5

After x years the model of the equation will be y = ($2500)(1.04)^x

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3 years ago

Read 2 more answers

The length of a rectangle is 3 units shorter than one-third of the width, x.

AveGali [126]

$\frac{8x}{3} - 6$ is the expression that represents the perimeter of rectangle

Solution:

Let "x" represent the width of rectangle

Given that length of rectangle is 3 units shorter than one-third of the width x

length of rectangle = one-third of the width x - 3

$\text{ length of rectangle} = \frac{1}{3}x - 3 = \frac{x}{3} - 3\\\\\text{ length of rectangle} = \frac{x}{3} - 3$

The perimeter of rectangle is given as:

<h3>perimeter of rectangle = 2(length + width)</h3>

Substituting the known values we get,

$\text{ perimeter of rectangle }= 2(\frac{x}{3} - 3 + x)\\\\\rightarrow 2(\frac{x - 9 + 3x}{3})\\\\\rightarrow 2(\frac{4x-9}{3})\\\\\rightarrow\frac{8x-18}{3}\\\\\rightarrow\frac{8x}{3} - \frac{18}{3}\\\\\rightarrow\frac{8x}{3} - 6$

Thus perimeter of rectangle is $\frac{8x}{3} - 6$

Thus option 1 is correct

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3 years ago

In a certain country telephone numbers have 9 digits. the first two digits are the area code and are the same within a given are

irga5000 [103]

Using the counting principle, the total number of possible telephone numbers is given by N = 1 * 1 * 9 * 10 * 10 * 10 * 10 * 10 * 10 = 9,000,000

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3 years ago