All categories

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.

You might be interested in

Which equation represents the line that passes through (–6, 7) and (–3, 6)? y = –x + 9 y = –x + 5 y = –3x – 11y y = –3x + 25

Svetllana [295]

Step $1$

<u>Find the slope of the line</u>

we know that

the formula to calculate the slope between two points is equal to

$m=\frac{(y2-y1)}{(x2-x1)}$

Let

$A(-6,7)\\B(-3,6)$

substitute the values

$m=\frac{(6-7)}{(-3+6)}$

$m=\frac{(-1)}{(3)}$

$m=-1/3$

Step $2$

with the slope m and the point $A(-6,7)$ find the equation of the line

we know that

the equation of the line in the point-slope form is equal to

$y-y1=m*(x-x1)$

substitute the values

$y-7=(-1/3)*(x+6)$

$y=(-1/3)x-2+7$

$y=(-1/3)x+5$

therefore

<u>the answer is</u>

$y=(-1/3)x+5$

4 0

3 years ago

Read 2 more answers

What is bigger 0.075 or 0.75 and why

hodyreva [135]

Answer:

0.75

the reason is because if we round it to the nearest tenth . 0.75 becomes 0.8. and 0.075 becomes 0.1 . 0.8 is 8/10th of 1. 0.1 is 1/10th of 1. therefor 0.8 is bigger

6 0

3 years ago

In a multiple choice exam, there are 5 questions and 4 choices for each question (a, b, c, d). Nancy has not studied for the exa

Elina [12.6K]

Answer: a) 0.07910, b) 0.000976, c) 0.7626

Step-by-step explanation:

Since we have given that

Number of questions = 5

Number of choices = 4

P(getting correct) = $\dfrac{1}{4}=0.25$

a) the ﬁrst question she gets right is the 5th question?

P(getting 4 wrongs answers and one right answer) is given by

$(1-0.25)^4\times 0.25\\\\=0.75^4\times 0.25\\\\=0.07910$

b) she gets all of the questions right?

P(all right )= $0.25^5=0.000976$

c) she gets at least one question right?

1-P(All of them wrong)

$=1-(1-0.25)^5\\\\=1-0.7565\\\\=1-0.2373\\\\=0.7626$

Hence, a) 0.07910, b) 0.000976, c) 0.7626

8 0

3 years ago

Ella completed 3/8 of a puzzle during recess on Tuesday. Joy completed two six of the same puzzle during recess on Wednesday. ho

gavmur [86]

Well u have to make the denominator the same so u multiply 3/8 by 3 and get 9/24, then multiple 2/6 by three and get 8/24. Add them, 9/24+8/24 and u get 17/24

6 0

3 years ago

Solve for x: 3 over 3x+ 1 over x+4= 10 over 7x

hram777 [196]

Answer:

Step-by-step explanation:

3/3x + 1/x+4 = 10/7x

3/3x + 1/x+4 = 10/7x , x=0,x=-4

1/x + 1/x+4 = 10/7x

1/x + 1/x+4 - 10/7x = 0

7(x+4)+7x-10(x+4) / 7x*(x+4) = 0

7x+28+7x-10x-40 / 7x*(x+4) = 0

4x-12 / 7x*(x+4) = 0

4x-12=0

4x-=12

x=3,x=0,x=-4

x=3

7 0

3 years ago