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3 years ago

Explain how the sum and difference formula cos(A+/- B) = cosA cosB -/+ sinA sinB could be useful?

2 answers:

7 0

You could find the exact value of cos of 15 degrees by using cos(45 - 30):-

cos(45 - 30) = cos 45cos30 + sin45 sin30 = 1 /sqrt2 * sqrt3/2 + 1/sqrt2* 1/2

serg [7]3 years ago

6 0

One way it's useful is in the application of phasors in physics. Phasors require you to add up vectors of two different angles, so the cosine angle addition formula can be used if you already know the cosine and sine of the original vector angles.

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Suppose you go to the grocery store and spend $92.54 for the purchase of 12 items. What is the mean price per item

ikadub [295]

Answer:

If its multiple choice then any number between 7 and 8 but closer the 8 should be the answer. If not, then I don't know

Step-by-step explanation:

92.54/12 = 7.71

8 0

2 years ago

Help me please 10 points no links or I report

Kipish [7]

Answer:

B. 5

Hope it helps!

Step-by-step explanation:

It lists green 5 times.

3 0

3 years ago

john has us and foreign stamps in his album. the ratio of the numer of us stamps to foreign stamps is 5:2. after paul gives him

VLD [36.1K]

Answer:

The number of U.S stamp he has is 120.

Step-by-step explanation:

John has us and foreign stamps in his album. the ratio of the number of U.S stamps to foreign stamps is 5:2.

After Paul gives him 12 foreign stamps the ratio becomes 2:1.

Now, to find the number of U.S stamps.

Let the U.S stamps be $x.$

And the foreign stamps be $y.$

Now, to solve by using cross multiplication method:

So, the ratio is:

$\frac{x}{y} =\frac{5}{2}$

By cross multiplying we get:

$2x=5y$

Dividing both sides by 2 we get:

$x=\frac{5y}{2}$ ......(1)

Now, after Paul gives him 12 foreign stamps the ratio becomes:

$\frac{x}{12+y} =\frac{2}{1}$

By cross multiplying we get:

$x=24+2y$

Putting the value of $x$ as we get in above equation (1):

$\frac{5y}{2} =24+2y$

Multiplying both sides by 2 we get:

$5y=48+4y$

Subtracting both sides by 4y we get:

$y=48.$

The number of foreign stamps = 48.

Now, to get the number of U.S stamps by putting the value of $y$ in equation (1):

$x=\frac{5\times 48}{2}$

$x=\frac{240}{2}$

$x=120.$

Therefore, the number of U.S stamp he has is 120.

7 0

4 years ago

Point slope form. (-5,-1) and (6,-5)

TEA [102]

Step-by-step explanation:

The point-slope form of an equation of a line:

$y-y_1=m(x-x_1)$

m - slope

(x₁, y₁) - point on a line

The formula of a slope:

$m=\dfrac{y_2-y_1}{x_2-x_1}$

We have two points (-5, -1) and (6, -5). Substitute:

$m=\dfrac{-5-(-1)}{6-(-5)}=\dfrac{-5+1}{6+5}=-\dfrac{4}{11}$

Put the value of a slope and coordinates of a point to the equation of a line:

$(-5,\ -1),\ m=-\dfrac{4}{11}\\\\y-(-1)=-\dfrac{4}{11}(x-(-5))\\\\y+1=-\dfrac{4}{11}(x+5)$

$(6,\ -5),\ m=-\dfrac{4}{11}\\\\y-(-5)=-\dfrac{4}{11}(x-6)\\\\y+5=-\dfrac{4}{11}(x-6)$

6 0

3 years ago

Which of the following is a rational number? EXPLAIN WHY FOR BRAINLIEST

Romashka-Z-Leto [24]

It’s B because it equals -8 when simplified which is a rational number

7 0

3 years ago