Cho alpha+ beta+ gamma = pi. Chứng minh A) sin alpha + sin beta + sin gamma = 4cos alpha/2*cos beta/2*cos gamma /2

Answers

Answer 1

Answer:

It is proved .

Step-by-step explanation:

[tex]\alpha +\beta +\gamma =\pi.....(1)\\\\sin\alpha + sin\beta +sin\gamma=4 cos\frac{\alpha}{2}cos\frac{\beta}{2}cos\frac{\gamma}{2}[/tex]

Take LHS

[tex]=sin\alpha + sin\beta +sin\gamma\\\\=2 sin \frac{\alpha +\beta }{2} cos\frac{\alpha -\beta }{2} + sin\gamma\\\\=2 sin\frac{180-\gamma}{2}cos \frac{\alpha - \beta}{2}+2 sin\frac{\gamma}{2}cos\frac{\gamma}{2}\\\\=2 cos\frac{\gamma}{2}cos \frac{\alpha - \beta}{2}+2 sin\frac{\gamma}{2}cos\frac{\gamma}{2}\\\\=2 cos\frac{\gamma}{2}\left [ cos \frac{\alpha - \beta}{2}+sin\frac{180-\alpha-\beta}{2}\\ \right ]\\\\=2 cos\frac{\gamma}{2}\times 2 cos\frac{\alpha}{2}cos\frac{\beta}{2}\\[/tex]

[tex]=4 cos\frac{\alpha}{2}cos\frac{\beta}{2}cos\frac{\gamma}{2}[/tex]

Hence proved.


Related Questions

what is the degree of polynomial x^2y^2+y^3+4?

Answers

Answer:

The degree of the polynomial ≈ 4

Step-by-step explanation:

The degree of a polynomial, is given by the highest value of the sum of the exponents (powers) of the of the variables (monomials) that are present in the polynomial expression

The given polynomial expression is x²·y² + y³ + 4

The sum of the exponents; 2 + 2 = 4, and 3

The sum of exponents 4 > 3

Therefore, the degree of the polynomial = 4.

PLS HELP ILL MARK BRAINLIEST Complete each sentence with minimum or maximum and the corresponding numeric values. The _____________ value of f(x) = –|x – 4| – 5 is __________ when x = _________ . The _______ value of f(x) = x2 – 2x +­ 1 is ___________ when x = _________ .

Answers

Answer:

Step-by-step explanation:

1) the maximum value of f(x) = –|x – 4| – 5 is -5 when x = 4

2) the minimum value of f(x) = x2 – 2x +­ 1 is  0 when x = 1

Find the indicated area of the sector surrounded in bold . Use 3.14 for pi!

Answers

Answer:

75.4 yd²

Step-by-step explanation:

Formula for Area of a sector when the central angle is given in degrees is given as :

θ/360 × πr²

Where:

Central angle = θ = 135°

Radius = r = 8yd

π = 3.14

Hence,

135/360 × 3.14 ×(8yd)²

= 75.36 yd²

Approximately the Area of the sector = 75.4 yd²

Date
Page
Out
of
100 students who appeared in
grade.VIII annual examination
of
Ram
Janaki Secondary School.60 passed in
mothematics, 50 in science and 20 students
passed in both subject find how
many
failed in both subject ? Aso show above information
student
in Venn-
bright
Venn-diagram
huan anatoa )
Sonnant Babase
eigshoos te
oloh​

Answers

Answer:

10 student failed in both subjects.

Step-by-step explanation:

Since out of 100 students who appeared in grade VIII annual examination of Ram Janaki Secondary School, 60 passed in mathematics, 50 in science and 20 students passed in both subjects, to determine how many failed in both subjects the following calculation must be performed:

(100 - 20) - (60 - 20) - (50 - 20) = X

80 - 40 - 30 = X

40 - 30 = X

10 = X

Therefore, 10 student failed in both subjects.

Brainliest + 20 points goes to whoever answers correctly also if you want more points then answer my others

Answers

The fourth option is the most likely

PLEASE HELP!! The green line below *blank*. Check all that apply.

A. is parallel to the x-axis

B. crosses the origin

C. is in the xy-plane

D. crosses the y-axis

Answers

Answer:

D. crosses the y-axis

[tex]{ \tt{crosses \: y - axis \: at \: y = 5}}[/tex]

Solve the following system of equations by substitution. PLEASE HELP!

Answers

Answer:

(1,-1)

Step-by-step explanation:

y = -1

5x+7y = -2

Substitute the first equation into the second

5x + 7(-1) =-2

5x -7 = -2

Add 7 to each side

5x-7+7 = -2+7

5x= 5

Divide by 5

5x/5 = 5/5

x =1

(1,-1)

in the similar triangle ABE and triangle CDE,AB=10cm,ED=4cm,CD=8cm find the length of BC​

Answers

9514 1404 393

Answer:

  BE = 5 cm

Step-by-step explanation:

Your problem statement asks for the length of BC. There is no segment BC. Points B and C are in different triangles.

The length of segment BE can be found from the proportion ...

  BE/DE = AB/CD

  BE = DE·AB/CD = (4 cm)(10/8)

  BE = 5 cm

You are 3 times older than your younger sister and you are 12 years old. Write an equation to solve for your sister's age​

Answers

the answer to this question is 36 cause you do 3 times 12


X^2 +
1/x^2
+12(x+1/x) +38,

Answers

Answer:

44

Step-by-step explanation:

An item costs $386 before tax, and the sales tax is $15.20.
Find the sales tax rate. Write your answer as a percentage.

Answers

Answer:

Sales tax rate = 3.94%

Step-by-step explanation:

[tex]Sales \ tax \ rate = \frac{15.20}{386} \\\\Sales \ tax \ rate = \frac{38}{965} \\\\[/tex]

Sales tax rate = 0.039378... ⇒ 3.94%

At the market you can buy 5 bags of apples for $23.60. At the farm you can buy 7 apples for $32.76. Which is the better deal

Answers

Answer:

Market

Step-by-step explanation:

Market : 5 bags = $23.60

Farm : 7 apples = $32.76

Market = $23.60 ÷ 5

= $4.72 each BAG

Farm = $32.76 ÷ 7

= $4.68 each APPLE

Thus, market is the better deal because you will get 5 bags of apple for $4.72 for each bag.

Brainliest goes to whoever answers correctly and explains

Answers

Answer:

The answers are below

Step-by-step explanation:

1 - 6ft

2 - 8 years

3 - 9ft

Find the median of 3,4,6,2,2,9,2,10

Answers

The answer is 4.75 you just need to add all of the numbers and then divide it to the total sum :)

Carry On Learning (◕ᴗ◕✿)

To find the median or middle, first put the numbers in order from least to greatest.
2,2,2,3,4,6,9,10
Then find the middle number. This set has two numbers since it is an even amount. 3,4
So you add those numbers
3 + 4 = 7
Then divide by 2
7/2 = 3.5
3.5 is the median for this set

I always think of the median of a highway. It is in the middle between both sides.

What are the roots of the equation 9x^2-42x+50=0 in simplest a+bi form?

Answers

Answer:

-7/3 +\- 1/3i

Step-by-step explanation:

divide rs 50000 bettween two charties in the ratio of 1/10: 1/15
TELL PLEASE

Answers

Answer:

sorry

Step-by-step explanation:

i dont know

sjksiisje

jsjsjdjdjdj

sjjsjd

Answer:

30000 : 20000

Step-by-step explanation:

Given the ratio

[tex]\frac{1}{10}[/tex] : [tex]\frac{1}{15}[/tex] ( multiply both parts by 30 the LCM of 10 and 15, to clear the fractions )

= 3 : 2

sum the parts of the ratio, 3 + 2 = 5 parts

Divide the amount by 5 to find the value of 1 part of the ratio

50000 ÷ 5 = 10000 ← value of 1 part of the ratio, then

3 parts = 3 × 10000 = 30000

2 parts = 2 × 10000 = 20000

Then

50000 = 30000 : 20000 in the ratio 3 : 2

Can somebody help me

Answers

5 (step by step below)

Which of these r-values represents the weakest correlation
A 0.6
B 0.3
C 0.5
D 0.4

Answers

Answer:

B

Step-by-step explanation:

0.3 is weakest

24 : 56 is equivalent to 3 : __

Answers

Answer:

3 : 7

Step-by-step explanation:

24/56 = 3 / 7

Answer:

3:7 helpful answer to your question have a nice evening

factorise fully the expression 2d^2-7d

Answers

Answer:

d(2d-7)

Step-by-step explanation:

2d^2 -7d

take common

=d(2d-7)

Answer :

[tex] \large \boxed{ \rightarrow d(2d - 7)}[/tex]

Solution :

[tex] \rightarrow2d {}^{2} - 7d[/tex]

[tex] \rightarrow d(2d - 7)[/tex]

[tex] \mathfrak{hope \:it \: helps \: you.....}[/tex]

Need help with this??? Please!!!

Answers

Answer:

the first option

Step-by-step explanation:

(f-g)(x) simply means to subtract both expressions. really literally.

and we go through it power by power of x.

the highest power/exponent of x is 3 (x³). only f(x) has one.

so, -7x³ is the first part of f-g.

next is x².

11x² - 6x² = 5x², which is the second part of f-g.

next is x.

-8x - (-14x) = -8x + 14x = 6x, which is the third part of f-g.

next is x⁰ (in other words, no x, just a constant).

4 - (-3) = 4 + 3 = 7, which is the 4th part of f-g.

we have no x to the power of -1 or -2, so we have -3

0 - (-4x‐³) = 4x‐³, which is the last part of f-g.

so, it is clearly the first answer option.

hii guys I'm sorry I am close to failin, and I sorry tay I'm asking a lot for questions :c ​

Answers

Answer:

A≈87.96

Step-by-step explanation:

A=2πrh+2πr2

= 2pi(2)(5) + 2pi(2)2

Answer:

Hello! answer: 87.92

Step-by-step explanation:

Im a little rusty on these but the answer I believe would be 87.92

2 × 2 × 3.14 = 12.56

2 × 2 × 3.14 = 12.56

4 × 3.14 = 12.56 12.56 × 5 = 62.8

12.56 + 12.56 + 62.8 = 87.92

Hope that helps!

List all the possible numbers for ALL 4 Quadrants (in terms of negative, positive).










What Quadrant would the following numbers be in:

-4, -6 ______
+5, +5______
-4, +1 ______
+3, -7 _____

Answers

JxkskKzk lflodlslslslss

find the first 5 terms in 3n^2/2

Answers

Here is the answer .......

4/10 + 5/100
Pls help now

Answers

Answer:

4/10 + 5/100=  9/20

Step-by-step explanation:

Answer:

9/20

Step-by-step explanation:

reduce the fraction with 2

4/10+5/100

2/5+5/100

2/5+1/20

write all numerators above the least common denominator 20

8+1/20

8+1=9

9/20

Arianna earns a weekly salary of $400 plus a 6.5% commission on sales at a gift shop. How much would she make in a workweek if she sold $4800 worth of merchandise?

Answers

Answer:

712

Step-by-step explanation:

400+6.5%of 4800

312+400=712

Cost per item: $6.06 item sold: 64321 total profit: $25123.5 sale price:?

Answers

Answer:

0.39063241

Step-by-step explanation:

cost per item: 6.06

items sold: 64321

total profit: 25123.5

sale price: ?

x = number of items

64321x - 6.06x = 25123.5

64314.94x = 25123.5

x = 25123.5/64314.94 = 0.39063241

A plane has traveled 26 miles on a course heading 48º east of north. How far north (x) has the plane traveled at this point, to the nearest tenth of a mile?

Answers

Answer: [tex]17.4\ \text{miles}[/tex]

Step-by-step explanation:

Given

A plane has traveled 26 miles on a course heading [tex]48^{\circ}[/tex] east of north

Taking the component of travel in North direction

The distance traveled in North is given by with the help of figure

[tex]\Rightarrow x=26\cos 48^{\circ}\\\\\Rightarrow x=26\times 0.669\\\\\Rightarrow x=17.4\ \text{miles}[/tex]

The triangles shown below are similar. Find the length of QS.

Answers

Answer: The value of QS is 8 cm.

Step-by-step explanation:

First calculating the side QT.

As per given figure:

ΔPQT ≈ ΔRST

[tex]\frac{PQ}{RS}=\frac{QT}{ST}[/tex]

Given:

PQ = 9 cm

RS = 3 cm

ST = 4 cm

Now putting all the given values in the above expression, we get:

[tex]\frac{PQ}{RS}=\frac{QT}{ST}\\\\\frac{9cm}{3cm}=\frac{QT}{4cm}\\\\QT=12cm[/tex]

Now calculating the value of QS.

QT = QS + ST

12 cm = QS + 4 cm

QS = 12 cm - 4 cm

QS = 8 cm

Thus, the value of QS is 8 cm.

can somebody help me frl frl cause I'm failing ​

Answers

i’m pretty sure the answer is 8pi, but here’s what i did to answer it :)
Other Questions
13. The students must have obeyedtheir teachers.a)Their teachers might have obeyed bythe students.O2)Their teachers might have beenobeyed by the students.O3)Their teachers must have been obeyedby the students.O4)Their teachers must have obeyed bythe students. Need help, Dont know what to put!!!!! Scientists today use satellites as well as telescopes to observe the universe. Suggest one waythat developments in equipment have changed the information scientists collect aboutplanets. Help me I don't know any Your assignment is to write a summary of The Secret Garden. Remember, when summarizing a fiction text, you should briefly retell the story, without giving away the ending. PLEASE HELP ME ITS DUE IN 30 MINUTES THANKS =) If A and B are (-2,-2) and (2,-4). Find the coordinates P such that AP=3/7 AB and P lies on the line segment ab Tetrodotoxin is a potent toxin found in a variety of organisms including the pufferfish. The toxin binds to the extracellular side of the Na+ channel and prevents channel opening. This leads to paralysis of muscles, including the diaphragm. Death from respiratory failure can occur after ingestion of as little as 1 mg of the toxin. Why does this toxin cause paralysis? Question 7 options: The axon membranes become over-depolarized. The Na+ channels remain in the inactive, refractory state. The Na+ channel does not open wide enough to allow enough Na+ through the channel. The membrane depolarization is not amplified along the axon. cite dois exemplos de condutas que representem infrao ao Cdigo de tica e Deontologia da Fisioterapia e quais devem ser as condutas adequadas do ponto de vista tico. design an if-then-else statement or a flowchart with a dual alternative decision structure that displays speed is normal if the speed variable is within the range of 24 to 56. if speed holds a value outside this range, display speed is normal Which substance is an electrolyte?A)C2H5OH(C)B)NaOH(s)C)H2(g)D)C6H1206 (s) Significant others are individuals that are not of any significance to help form our socialization. Please select the best answer from the choices provided O F Next Save and Exit Mark this and return the measure of an exterior angle of a triangle is greater than the measure of either of its remove interior angles this is the answer for 'select the correct location on the image.Where are the photoreceptors located inside a human eye?' help help help help help Andres went out to a restaurant for dinner. His total bill before tax and tip was $27.30. He was charged an additional 9% tax and he also paid a 15% tip on the original bill. [tex] {10}^x = 5[/tex] What is x? = 5/log 10 ^10 x= In 5 x=log 10^5x=1/2 What does good exposition do for the reader of a story? TIENDA DE LA GRACIATiendas 100Trabajadores 324Promedio diario de clientes 760 Camisas 612Pantalones 4041. Cuntas Tiendas de la Gracia hay?2. Cul es el promedio diario de clientes en cada tienda?3. Cuntos trabajadores hay en las Tiendas de la Gracia?4. Cuntos pantalones hay en cada tienda?5. Y camisas? answer the following questions (1-5) according to the TIENDA DE LA GARCIA chart. Mrs. Allen baked 9 pies. She sliced each pie into pieces that are 1/5 of a whole. How many pieces of pie does she have?thx Find the circumference