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2 years ago

11

___ cosb =1/2 sin(a+b)+sin(a-b)?

2 answers:

vodomira [7]2 years ago

8 0

Answer:

That would be sina.

Step-by-step explanation:

sin(a+b) = sinacosb + cosasinb

sin(a-b) = sinacosb - cosasinb

Adding we get sin(a+b) + sin(a-b) = 2sinaccosb

so sinacosb = 1/2sin(a+b) + sin(a-b)

dem82 [27]2 years ago

6 0

Answer:

sina

Step-by-step explanation:

We have

sin(a+b) = sina cosb + cosa sinb ---------------------eqn 1

sin(a-b) = sina cosb - cosa sinb ---------------------eqn 2

eqn 1 + eqn 2

sin(a+b) + sin(a-b) = sina cosb + cosa sinb + sina cosb - cosa sinb

sin(a+b) + sin(a-b) = 2sina cosb

$sina\times cosb =\frac{1}{2}(sin(a+b) + sin(a-b))$

So answer is sina

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A car rental firm has the following charges for a certain type of car: $25 per day with 100 free miles included, $0.15 per mile

Eddi Din [679]

y = 25 + 0.15x is the equation for relating the cost y to the number of miles x that you drive the car

<em><u>Solution:</u></em>

Let "y" be the total cost of car rental

Let "x" be the number of miles you drive the car for more than 100 miles

<em><u>A car rental firm has the following charges for a certain type of car:</u></em>

$25 per day with 100 free miles included, $0.15 per mile for more than 100 miles

<em><u>Suppose you want to rent a car for one day, and you know you'll use it for more than 100 miles</u></em>

Therefore,

Car is rented for one day

You will use it for more than 100 miles

Therefore, equation is framed as:

Total cost = $ 25 + 0.15(number of hours)

$Total\ Cost = 25 + 0.15x\\\\y = 25 + 0.15x$

Thus the equation for relating the cost y to the number of miles x that you drive the car

7 0

2 years ago

A building engineer analyzes a concrete column with a circular cross section. The circumference of the column is 18 \pi18π18, pi

Whitepunk [10]

Answer:

$A=81\pi $ m^2$

Step-by-step explanation:

Circumference of the column $=18\pi $ meters$

Circumference of a circle $=2\pi r$

Therefore:

$2\pi r =18\pi $ meters\\2r=18\\r=18 \div 2\\$Radius, r=9 meters$

Area of a Circle $=\pi r^2$

Since radius of the cross section of the column =9 meters

Area of the cross section of the column

$=\pi *9^2\\=81\pi $ m^2$

5 0

2 years ago

Which sets of numbers contain whole numbers? Check all that apply. Negative 2 and StartFraction 5 Over 6 EndFraction, negative 5

Zigmanuir [339]

Answer:

The whole numbers are 0 and 79.

Step-by-step explanation:

The numbers provided are as follows:

$-2\frac{5}{6},\ -54,\ -4,\ -57,\ -89,\ 79,\ \frac{6}{9},\ \\\\-19\frac{2}{3},\ \frac{2}{4},\ 0,\ \frac{2}{7},\ -3,\ -2, -7,\ -8,\ \\\\\frac{1}{8},\ -\frac{4}{8},\ 1\frac{3}{8},\ -\frac{7}{8}$

Whole numbers are a set of natural positive numbers and 0. This set basically consists of counting discrete numbers.

Such as: 0, 1, 2, 3, 4, 5....

From the provided set of numbers the whole numbers are:

S = {79 and 0}

Thus, the whole numbers are 0 and 79.

8 0

2 years ago

Which three-dimensional figure has half the number of vertices as the rectangular prism?

monitta

Answer:

1. The rectangular prism is a right prism with rectangular bases (check the picture)

2. It has 8 vertices, so we are looking for 3d figures with 4 vertices.

3. A face can have at least 3 vertices, and the 4th must be outside of the plane determined by the first 3 vertices. This makes 4 vertices in total.

4. The 3d figure described in step 3 is a pyramid.

so the answer is prism

Step-by-step explanation:

4 0

2 years ago

Read 2 more answers

10 times as many as 1 ten is ______ tens.

anyanavicka [17]

Same 10 tens I guess

5 0

2 years ago