prove that : Cos 2A =cot^2-1/cot^2+1​

Answers

Answer 1

Answer:

[tex] \cos(2A) = { \cos }^{2} A - { \sin }^{2} A \\ = { \cos }^{2} A - \frac{1}{ \csc {}^{2} A} \\ \\ = \frac{( { \cos}^{2} A. \csc {}^{2}A ) - 1}{ { \csc }^{2} A} \\ \\ = \frac{( \frac{ { \cos}^{2}A }{ { \sin }^{2} A}) - 1 }{ { \csc }^{2} A} \\ \\ = \frac{ { \cot}^{2}A - 1 }{ { \csc}^{2} A} [/tex]

but csc²A = cot²A + 1:

[tex] = \frac{ { \cot}^{2}A - 1 }{ { \cot }^{2}A + 1 } [/tex]

# proved


Related Questions

The area of a square is 16cm²
What is the perimeter?

Answers

Answer:

Perimeter = 16 cm

Step-by-step explanation:

The formula for a square's area  = s^2 where the length of the side is s.

s^2 = 16                   Take the square root of both sides

sqrt(s^2) = sqrt(16)

s = 4

The perimeter is the same

P = 4*s

P = 4 * 4

P = 16

Answer:

16

Step-by-step explanation:

Square root of 16 = 4cm

4 sides, 4 * 4 = 16cm

Solve the equation 4(z−3)=2z9+22 using the balancing method.
z=

Answers

Answer:

z = 9

See my attachment below for step-by-step explanation.

Find the sum: xy+6xy​

Answers

Answer:

7xy

Step-by-step explanation:

I NEED HELP PLEASE HELP ME

Answers

The answer to the question is B.

Shirley is going to have the exterior of her home painted Tim’s painting charges $250 plus $14 per hour colorful paints charges 22 per hour how many hours with the job need to take bottoms painting to be the better deal deal

Answers

Answer:

x=31.25

Step-by-step explanation:

250+14h=22h

250=22h-14h

250=8h

h=250/8

h=31.25

NEED THE ANSWER ASAP, PLEASE HELP!! What are the coordinates of the focus of the parabola?

y=−18x2−2x−4

Answers

Answer:

Vertex is (-8, 4)  not one of the answers offered!

Step-by-step explanation:

Factor -1/8 out of the first two terms. Leave a space inside parentheses in which to add a number.

[tex]y=-\frac{1}{8}(x^2 + 16x + \text{-----})-4[/tex]

Complete the square by squaring half the coefficient of x and adding it in the space.

[tex](\frac{16}{2})^2=64[/tex]

Add 64 in the space you made, then compensate for that at the end of the expression by subtracting  [tex]-\frac{1}{8}(64)=-8[/tex]

[tex]y=-\frac{1}{8}(x^2+16x+64)-4+8\\y=-\frac{1}{8}(x+8)^2+4[/tex]

The x-coordinate of the vertex is the opposite of +8, the number inside the parentheses.  The y-coordinate of the vertex is the number at the end of the expression.

V(-8, 4)

Vicky wanted to investigate water evaporation. She placed 50 mL of distilled water in three identical glass jars. She left one jar in the sunlight, one jar in the dark, and one jar in a shady area. After four hours, she measured how much water was still in each jar.

Which of the following variables was held constant in the experiment?
A.
amount of water in jars at the end of the investigation
B.
air temperature
C.
light exposure
D.
amount of water placed in jars

Answers

Answer c Light exposure

please help me out if you can​

Answers

Answer:

180° is the measures of the supplement Step-by-step explanation:please click on star

Answer:

x=60°(Suppliment)

Put the above value =60°

second angle=120°

SEE the IMAGE FOR SOLUTION

help me find x

help please

Answers

Answer:

[tex]4\sqrt{6}[/tex]

[tex]\frac{sin\left(90\right)}{x}=\:\frac{sin\left(60\right)}{\left(\frac{\left(6\cdot \:sin\left(90\right)\right)}{sin\left(45\right)}\right)}[/tex]

Step-by-step explanation:

Answer: 4sqrt(6)

Explanation:

Sin(theta) = opp/hyp => hyp = opp/sin(theta)

Find opp:

opp = sqrt(6^2 + 6^2)
= sqrt(72)
= 6sqrt(2)
= 6 x 1.41

Hyp(also is x) = (6 x 1.41)/Sin(60°)
= (6 x 1.41 )/0.86
= 9.83
= 10 (round up)

And 4sqrt(6) = 9.79 = 10 (round up)

Thus I concluded that x = 4sqrt(6)

50 km/h to miles per hour

Answers

31.0686 miles per hours

31.069 miles per hour

can u help me with all the questions​

Answers

Answer:

b) -4xy

c) a³+b³

d)4x²+16xy+16y²+3x+4y

Step-by-step explanation:

b)expand each square bracket and minus them

c)times everything in the second bracket by a and then b

d)expand the first square bracket and add it to the other bracket

find the value of X ?​

Answers

Step-by-step explanation:

[tex]thank \: you[/tex]

ANSWER:
x=30°

EXPLANATION:
the line adds up to 180. subtract 90 and 60 from 180 to get 30.

Find the perimeter and area , pls help me on this I’ll give brain list :)

Answers

Answer:

area= x^2

perimiter= 4x

Answer:

area of square = l² = x ² cm²

perimeter of square = 4 l = 4 x cm

mark me as brainliest

Type the correct answer in each box. A circle is centered at the point (-3, 2) and passes through the point (1, 5). The radius of the circle is units. The point (-7, ) lies on this circle.

Answers

Answer:

The circle has like an equation: (x+3)²+(y-2)²=r²

If x=1 then y=5 ==>(1+3)²+(5-2)²=r²==>4²+3²=r²==>r=5 (the radius)

if x=-7 then (-7+3)²+(y-2)²=25 ==>  (y-2)²=25-16==>y=2+3 or y=2-3

The points (-7,5) and (-7,-1) are on the circle.

please help thank so much

Answers

Answer:

A) y = 4

B) x = 5

Step-by-step explanation:

for a), the line is horizontal. The y-value doesn't change--it stays at 4.

For b), the line is vertical. So the x-value doesn't change--it stays at 5.

What fraction of $1,75 is 77c

Answers

Answer:

44 :

Step-by-step explanation:

77/175 = 0.44

0.44x100

solve: k/3+4-5k=-2k (LOOK AT PICTURE)​

Answers

The answer for this is k=3/2

A rectangle has a length of x and a width of 6x^3 + 3− x^2. Find the perimeter of the rectangle when the length is 5 feet

Answers

Answer:

1466 feet

Step-by-step explanation:

If length is 5 feet, x=5. The width will be 6*(5)^3+3-(5)^2=728 feet. The perimeter will be 2*(l+b)=2*733=1466 feet

there are 14 math teachers and 26 science at school today what is the ratio of math teachers and science at school?

Answers

Answer:

Answer is 7:20

It's basically asking "what is the ratio of math teachers to total teachers?" assuming there are only math and science teachers at this school. For the sake of simplicity, let's just go with that. We have 14 math teachers and 14+26 = 40 teachers total. The ratio of math to total is 14:40 which reduces to 7:20 when we divide both parts of the ratio by the GCF 2.

Step-by-step explanation:

Answer:

the ratio is

14:26

but you can leave the answer like this the two numbers can be divided by 2 so

14/2=7 and 26/2=13

then the answer is 7:13.

The expression 14^6 divided by 14^4 is equal to
1. 14^2
2. 1
3. 2
4. 14^10

Answers

Answer:

1. 14^2. answer..yehshhd

Answer:

14 2

Step-by-step explanation:

correct.

-21 - 8a = -5(a +6)
Step by step if possible

Answers

Answer:

Step-by-step explanation:

First multiply the -5 to (a+6)

The equation will look like this

-21 - 8a = -5a -30

then move the numbers around where you have a value times on one side, and a normal value on the other

add -5a to -8a, and add -21 to -30

the equation should look like this:

-13a = -51

then you need to get the a by itself, so divide -13 by -51

a= 13/51 (as a fraction with 13 on top)

Answer:

a = 3

Step-by-step explanation:

-21 - 8a = -5(a + 6)

-21 - 8a = -5a - 30

8a + (-5a) = 30 - 21

3a = 9

a = 9/3

a = 3

Suppose c = 5 and A = 85 degrees.

Answers

Answer:

a = 4.98

b = 0.44

B = 5

Concept:

Here, we need to know the idea of the Pythagorean theorem and basic trigonometry ratios.

Pythagorean theorem: a² + b² = c²

a = legb = legc = hypotenuse

Trigonometry ratios:

Sine = Opposite / Hypotenuse = O/HCosine = Adjacent / Hypotenuse = A/HTangent = Opposite / Adjacent = O/A

Solve:

**Disclaimer** The question did not clarify which place did it required to be rounded to as some of the values are infinite. I rounded to the hundredth place. If it is fine, then you may refer to my answers. If it is not, then you may tell me and I'll redo it.

Given information

c = 5

A = 85°

PART ONE: Find the value of [a]

sin (A) = Opposite / Hypotenuse = a / c

sin (85) = a / 5

a = 5 · sin (85)

a = 4.98

PART TWO: Find the value of [b]

cos (A) = Adjacent / Hypotenuse = b / c

cos (85) = b / 5

b = 5 · cos (85)

b = 0.44

PART THREE: Find the value of [B]

Since the triangle as a right angle sign, meaning it is a right triangle.

Therefore, the corner angle is 90°.

90 - 85 = 5°

Hope this helps!! :)

Please let me know if you have any questions

Help
me
please with questions 4, 5 and 6, THANKS

Answers

Answer:

hgzzrzdjjhhgccghjvcss

hgvvghjdszschkmbc

Step-by-step explanation:

bbhjvfdseaaasrfhujklknhgcffdzsshbjkhj

hggcfgbjvcfvjjhxsgj

0.736euros= 1us dollar

Answers

Answer:

0.86 United States Dollar

Step-by-step explanation:

any one solve these questions will mark brainliest the last three​ fast plz

Answers

(iii)

35+ x + 60 = 180

95 + x = 180

x = 180 – 95

x = 85

So; X = 85° ; < PON(iV)

x + 47 + 75 = 180

x + 122 = 180

x = 180 – 120

x = 58

So; x = 58° ; < COB

(Vi)

105 ° = 3 x° –> Opposite angles ,

x = 105 / 3

x = 35

3x = 3(35) = 105°

So; x = 35°

Only the figure (V) I didn't know I'm sorry:(

I hope I helped you^_^

Line Segments
Find ZX

Answers

Answer:

A:4.5

Step-by-step explanation:

all you need to do is count the spaces

-8n - 8(- 4-2n)
Anyone?

Answers

Answer:

8n+32 Thats if youre simplyifying it

8(4+n)

Jdbdksjdjskdjjdjd

If B is mid point of AE and AB is 25 what is AE

Answers

Answer:

50 i think not sure what kind a question this is

The double bar graph shows how long, on average, different
animals live both in the wild and in captivity.
Which animal's life span in captivity has the least difference from
its life span in the wild?
ears

Answers

Answer: Cheetah

Step-by-step explanation: I got it right on the test :)

The animal with the least difference is cheetah with a value of 5

From the double bar chart attached :

Life span in wild is = blue bar

Life span in wild is = blue bar Life span in captivity = brown bar

Calculating the approximate difference between the two bar values as obtained from the graph :

CHEETAH = 17 - 12 = 5

POLAR = 35 - 20 = 15

TIGER = 26 - 20 = 6

GIANT PANDA = 30 - 20 = 10

LEOPARD = 28 - 20

The animal with the least difference between it's span in the wild and in captivity is CHEETAH with a value of 5.

Learn more : https://brainly.com/question/8644324

Still do not understand how its work

Answers

Answer:

Step-by-step explanation:

The slope or, gradient is the rate of change of a linear function( a function which can be represented by a line). We find a slope between two arbitrary  pair of points( arbitrary means what the question given us). One point we are given is (0,4) and an another point we are given is (2,1). Now we use the slope formula,

[tex]\frac{change in y }{change in x}[/tex]

So let plug in the values,

[tex]\frac{4-1}{0-2} =\frac{3}{-2} =-\frac{3}{2}[/tex]

The slope is -3/2

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