PROVE THAT:

cos 20° - sin 20° = ​​ \sqrt{2}sin25°

Answers

Answer 1

Answer:

See below.

Step-by-step explanation:

[tex]\cos(20)-\sin(20)=\sqrt{2}\sin(25)[/tex]

First, use the co-function identity:

[tex]\sin(90-x)=\cos(x)[/tex]

We can turn the second term into cosine:

[tex]\sin(20)=\sin(90-70)=\cos(70)[/tex]

Substitute:

[tex]\cos(20)-\cos(70)=\sqrt{2}\sin(25)[/tex]

Now, use the sum to product formulas. We will use the following:

[tex]\cos(x)-\cos(y)=-2\sin(\frac{x+y}{2})\sin(\frac{x-y}{2})[/tex]

Substitute:

[tex]\cos(20)-\cos(70)=-2\sin(\frac{20+70}{2})\sin(\frac{20-70}{2})\\\cos(20)-\cos(70) =-2\sin(45)\sin(-25)\\\cos(20)-\cos(70)=-2(\frac{\sqrt{2}}{2})\sin(-25)\\ \cos(20)-\cos(70)=-\sqrt{2}\sin(-25)[/tex]

Use the even-odd identity:

[tex]\sin(-x)=-\sin(x)[/tex]

Therefore:

[tex]\cos(20)-\cos(70)=-\sqrt{2}\sin(-25)\\\cos(20)-\cos(70)=-\sqrt{2}\cdot-\sin(25)\\\cos(20)-\cos(70)=\sqrt{2}\sin(25)[/tex]

Replace the second term with the original term:

[tex]\cos(20)-\sin(20)=\sqrt{2}\sin(25)[/tex]

Proof complete.


Related Questions

prove that [tex]2/\sqrt{3} cosx + sin x= sec(\pi /6-x)[/tex]

Answers

Answer:

sec(π/6 - x) = R.H.S = 2/(√3cosx + sinx)  = L.H.S.

Step-by-step explanation:

sec(π/6 - x) = 1/cos(π/6 - x)

Using compound angle formula,

cos(A - B) = cosAcosB + sinAsinB where A = π/6 and B = x.

So, cos(π/6 - x) = cos(π/6)cosx + sin(π/6)sinx , cosπ/6 = √3/2 and sinπ/6 = 1/2

cos(π/6 - x) = cosπ/6cosx + sinπ/6sinx = (√3/2)cosx + (1/2)sinx

sec(π/6 - x) = 1/cos(π/6 - x)

= 1/(√3/2)cosx + (1/2)sinx = 2/(√3cosx + sinx)

= L.H.S

So, sec(π/6 - x) = R.H.S = 2/(√3cosx + sinx)  = L.H.S

Solve please. 5x+6=1 X=

Answers

Answer:

x = -1

Step-by-step explanation:

Given,

5x + 6 = 1

=> 5x = 1 - 6

=> 5x = -5

[tex] = > x = \frac{ - 5}{5} [/tex]

=> x = -1 (Ans)

Hello pls Asap plsssss

Answers

Option 3 or 4 would be your correct answer

pi = c/d solve for d?

Answers

Answer:

[tex]d=\displaystyle\frac{C}{\pi}[/tex]

Step-by-step explanation:

Hi there!

[tex]\pi =\displaystyle\frac{C}{d}[/tex]

Multiply each side by d:

[tex]d\pi =\displaystyle\frac{C}{d}*d\\\\d\pi=C[/tex]

Divide both sides by π:

[tex]d=\displaystyle\frac{C}{\pi}[/tex]

I hope this helps!

Suatu jenis bakteri, setiap detik akan membelah diri menjadi dua, jika pada saat permulaan ada 5 bakteri, berapakah jumlah bakteri setelah 10 detik? (geometric series=deret geometri)?

Answers

Answer:

Vc. Tính giai cấp

Step-by-step explanation:

Latanya buys 5 yard of blue fabric and 8 yards of green fabric. the blue fabric cost $2 dollars more than the green fabric.she pays a total of $ 62. what would be the combined cost of 1 yard of blue fabric and one yard of green fabric?

Answers

Answer: $10

Step-by-step explanation:

let x = the price of green fabric, then x+2 = blue fabric price

8x+5(x+2)=62

8x+5x+10=62

    13x+10=62

          13x=52

              x=4

price of green fabric=$4

price of blue fabric=$6

4+6=$10


A triangular pyramid has a base shaped like an equilateral triangle. The legs of the equilateral triangle are all 4 centimeters long, and the height of the equilateral triangle is 3.5 centimeters. The pyramid's slant height is 8 centimeters. What is its surface area?

Answers

Answer:

The surface area is 55 cm².

Step-by-step explanation:

The formula to compute the surface area of the triangular pyramid is:

[tex]SA=(0.50\times \text{Base Perimeter}\times h)+\text{Base Area}[/tex]

Here h is the slant height.

Compute the Base perimeter as follows:

Perimeter of the equilateral triangle = 3 × side

                                                            = 3 × 4

                                                            = 12 cm

Compute the Base area as follows:

Area of the equilateral triangle = 0.50 × side × height

                                                    = 0.50 × 4 × 3.50

                                                    = 7 cm²

Compute the surface area as follows:

[tex]SA=(0.50\times \text{Base Perimeter}\times h)+\text{Base Area}[/tex]

     [tex]=(0.50\times 12\times 8)+7\\=48+7\\=55\ \text{cm}^{2}[/tex]

Thus, the surface area is 55 cm².

The cost of a pizza at the local pizza shop has a base price of $12 for a cheese pizza, plus $2 for each additional topping? What is the value of the slope?

Answers

Answer:

$2.

Step-by-step explanation:

This is because the base price is $12, which means the constant is 12. The toppings are the only things you can add to the pizza, so the price of each additional topping is the slope of the pizza's cost. The slope is 2 dollars.

Hope this helps!

Answer:

2

Step-by-step explanation:

If we were to write a linear equation in slope-intercept form (y = mx + b where m = slope and b = y-intercept) of this situation, it would be y = 2x + 12 where y is the price and x is the number of toppings. This is because the price for every topping is 2x but the base price doesn't change, therefore it's a constant so it would be + 12. In this case, since m = slope, the slope is 2.

The population of a large U.S. city is 2,707,210. Which of the following best expresses this population?
A 2.7 × 106 C 2.707 × 106
B 2.7 × 107 D 27.07 × 106

Answers

Answer:

2.707 * 10^6

i think it is the best expression

how do you find the surface area of this triangular prism?

Answers

To find the area of a triangular prism you have to do A 1/2 bh or A bh/2 which means you have to multiply those two fractions and reduce them

Answer:

Find the area of the 2 triangle faces first and then find the area of the 3 rectangle faces and add them together to get [tex]159cm^{2}\\[/tex]

Step-by-step explanation:

Step 1: Find the surface area of the 2 triangles

[tex]\frac{(6)(5.5)}{2}[/tex] x2 = [tex]33cm^2\\[/tex]

Step 2: Find the surface area of the 3 rectangles

(6x7) x 3 = [tex]126cm^2[/tex]

Step 3: Add the 2 surface areas together

[tex]33cm^2\\[/tex] + [tex]126cm^2[/tex] = [tex]159cm^2[/tex]

Therefore the surface area of the prism is [tex]159cm^{2}[/tex]

(a+b)² = a²+2ab+b² prove that.​

Answers

Answer:

see explanation

Step-by-step explanation:

(a + b)²

= (a + b)(a + b)

Each term in the second factor is multiplied by each term in the first factor, that is

a(a + b) + b(a + b) ← distribute parenthesis

= a² + ab + ab + b² ← collect like terms

= a² + 2ab + b²

Answer:

(a+b) is squared which means (a+b)(a+b)

Lets prove it

= (a+b)(a+b)

= a(a+b) + b(a+b) (Here a will mutiply by (a+b) and b will mutiply with (a+b)

= a²+ab + ab + b²

= a²+ 2ab + b²

Hence proved (a+b)² = a²+ 2ab + b²

please click thanks and mark brainliest if you like :)


Evaluate the expression below for x =4 and y = 5.
x2 + 3(x + y)
When x = 4 and y = 5, x2 + 3(x + y)= |
(Type an integer or a decimal.)

Answers

Answer:

positive 35

Step-by-step explanation:

x2 + 3(x + y)        given

4(2) + 3(4+5)         problem

4(2) + 3(9)

8 + 27= 35

what is the radical of 5√72 PLZ HELP!

Answers

Answer: Exact Form: 30√2

Decimal Form:42.42640687…

Step-by-step explanation: Simplify the radical by breaking the radicand up into a product of known factors, assuming positive real numbers.

I hope this helped :)

Answer:

  30√2

Step-by-step explanation:

The radical portion of the given expression is √72.

__

Perhaps you want the simplest form of your expression. Factor out the perfect squares from under the radical.

  [tex]5\sqrt{72}=5\sqrt{36}\sqrt{2}=5\cdot 6\sqrt{2}=\boxed{30\sqrt{2}}[/tex]

ncert maths class 10 solution 5.1 4

Answers

Can you attach a picture to your question?

I would love to help you out.

Answer:

Step-by-step explanation:

NCERT Solutions for Class 10 Maths Chapter 5 Arithmetic Progressions Ex 5.1

           where is question ??

Which table represents a function?

Answers

Answer:

A

Step-by-step explanation:

it is A for every output y , there is only one input x

Answer:

A

Step-by-step explanation:

Because all the x-intercepts are different. Whereas all the other ones have repeats of numbers in the x-intercepts.

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Answers

Answer:

See explanation

Step-by-step explanation:

a) 15:20 - 12:35 = 14:80 - 12:35 = 2 hours and 45 minutes

b) 13:05 - 10:15 = 12:65 - 10:15 = 2 hours and 50 minutes

c) 6:50 - 4:30 = 2 hours and 20 minutes

d) 1:15pm - 9:55am = 13:15 - 9:55 = 12:75 - 9:55 = 3 hours and 20 minutes

Answer:

a) 15:20 - 12:35 = 14:80 - 12:35 = 2 hours and 45 minutes

b) 13:05 - 10:15 = 12:65 - 10:15 = 2 hours and 50 minutes

c) 6:50 - 4:30 = 2 hours and 20 minutes

d) 1:15pm - 9:55am = 13:15 - 9:55 = 12:75 - 9:55 = 3 hours and 20 minutes

Step-by-step explanation:

If a+8√5b = (8+√5)÷(8-√5) + (8-√5)÷(8+√5)

Answers

Answer:

3 or at least i think

Step-by-step explanation:

Answer:

a= 138/59 - 8√5b B=69√5/1180 - a√5/40

Step-by-step explanation:

yuh

At a computer manufacturing company, the actual size of computer chips is normally distributed with a mean of 1 centimeter and a standard deviation of 0.1 centimeter. A random sample of 16 computer chips is taken. What is the probability of thesample mean

Answers

THIS IS COMPLETE QUESTION

computer manufacturing company, the actual size of computer chips is normally distributed with a mean of 1 centimeter and a standard deviation of 0.2 centimeters. A random sample of 16 computer chip is taken. What is the probability that the sample mean will be below 0.95?

Answer:

the probability is P=0.045

Step-by-step explanation:

We were given mean of computer chips as 1 centimeter and a standard deviation of 0.1 centimeter

We were given

σ=0.1

n=16

We calculate:

Z=(0.95-1)/0.1 √16

Z=-0.125

Using the standard z- tables. to get the probability we have

P(X<0.95)=P(z<-0.115)=0.045

Therefore, probability is P=0.045

If you continue to subtract 6, what is the last number in the sequence before you get to 0? Explain how you got this answer.

Answers

Answer:

  6

Step-by-step explanation:

If x represents the last number, to get zero you must subtract 6 from it:

  x - 6 = 0

  x = 6 . . . . . . add 6 (undo the subtraction)

The last number before zero is 6.

solve -3.5 = 0.5x +0.5x+x

Answers

Answer:

x= 7/4 =1.750

Step-by-step explanation:

x= -1.75 is the answer

The value of a collectible coin can be represented by the equation y = 2 x + 15, where x represents its age in years and y represents its total value in dollars. What is the value of the coin after 19 years? $2 $23 $38 $53

Answers

Answer:

53$

Step-by-step explanation:

They tell you the equation of how much the coin is worth after x amount of years

Step 1: Substitute x=19 into the equation y=2x+15

y = 2(19) + 15

Step 2: Solve for y

y = 2(19) + 15

y = 38 + 15

y = 53

Therefore the coin is worth 53 dollars after 19 years

Answer:

53

Step-by-step explanation:

Got it correct on Edu. 2020

PLEASE HELP ASAP!!
Find the surface area of the regular pyramid shown in the accompanying diagram. If necessary, express your answer in simplest radical form.


A. 146.85 units²

B. 45+9√3 units²

C. 36+9√3 units²

D. 36+3√3 units²

Answers

The total surface area of the pyramid is 52 square units

The formula for calculating the area of the triangular based pyramid is expressed as;

[tex]TSA=Base \ Area+\frac{1}{2}ps[/tex] where;

p is the perimeter of the base

s is the slant height

Get the Base area

[tex]Base \ Area = \frac{1}{2}bh\\Base \ Area = \frac{1}{2}*6*\sqrt{5^2-3^2} \\ Base \ Area = \frac{1}{2}*6*\sqrt{25-9} \\ Base \ Area = \frac{1}{2}*6*\sqrt{16} \\ Base \ Area = \frac{1}{2}*6*4 \\ Base \ Area = \frac{24}{2} \\Base \ Area = 12 units^2[/tex]

Get the perimeter

Perimeter = 5 + 5 + 6

Perimeter = 16 units

Slant height = 5units

Substitute the given values into the formula above as shown;

[tex]TSA=12+\frac{1}{2}*16*5\\TSA=12+(8*5)\\\\TSA = 12 + 40\\TSA = 52 units ^2[/tex]

Hence the total surface area of the pyramid is 52 square units

Learn more here: https://brainly.com/question/23353623

Answer:

52squnits

Step-by-step explanation:

at the rate of 50 mph a car can travel 14.6 miles for each gallon of gas used. On a trip Mr. Hanson used 12.5 gallons of gas traveling at a speed of 50 mph. the number of miles covered during the trip was:

Answers

Answer:

182.5 miles in the rate of 50 mph.

Step-by-step explanation:

1 gallon = 14.6 miles in the rate of 50 mph

12.5 gallons = ?

12.5 × 14.6 = 182.5 miles in the rate of 50 mph.

The number of miles covered during the trip was 182.5 miles.

Given that, at the rate of 50 mph, a car can travel 14.6 miles for each gallon of gas used. On a trip, Mr Hanson used 12.5 gallons of gas travelling at a speed of 50 mph.

What is a unitary method?

The unitary method is a technique for solving a problem by first finding the value of a single unit, and then finding the necessary value by multiplying the single unit value.

Now, 1 gallon = 14.6 miles at the rate of 50 mph

12.5 × 14.6 = 182.5 miles in the rate of 50 mph.

Therefore, the number of miles covered during the trip was 182.5 miles.

To learn more about the unitary method visit:

https://brainly.com/question/22056199.

#SPJ2

Cada par de numeros esta a razon de 2:3

Answers

(0,8)+(7,-52) eso es la problema

PLEASE HELP! 17 points! Use the right-hand rule for magnetic force to determine the charge on the moving particle. This is a _____ charge.

Answers

Answer: Positive Charge

Answer:

negative

Step-by-step explanation:

When using the Right-Hand Rules, it is important to remember that the rules assume charges move in a conventional current (the hypthetical flow of positive charges).  In order to apply either Right-Hand Rule to a moving negative charge, the velocity (v) of that charge must be reversed--to represent the analogous conventional current.

The opposite charge is a negative charge.

Identify the sample as biased or unbiased and describe its type. John wanted to know about the popularity of a particular movie. He surveyed 20% of the people in 5 different theaters.

Answers

Answer: unbiased; simple random sampling

Step-by-step explanation:

From the question, we are informed that John wanted to know about the popularity of a particular movie and that he surveyed 20% of the people in 5 different theaters.

This is an unbiased sample. This is because everybody at the theaters have an equal chance of being chosen by John.

Also, it's a simple random sampling. This is because a subset of the entire population is randomly selected.

Please help me answer this question. -15 - g/3 = -5.
What is g?​

Answers

Answer:

g = -30

Step-by-step explanation:

-15 - g/3 = -5

Add 15 to each side

-15+15 - g/3 = -5+15

-g/3=10

Multiply by -3 to each side

-g/3 * -3  = 10*-3

g = -30

Answer:

g= -30

Step-by-step explanation:

after writing down the problem, multiply both sides of the equation by 3 to get  -45-g= =15. then subtract 15 from both sides to get g=-30, which is your answer. hope this helps!

A rectangular swimming pool has length 15w - 1 feet and width 9w + 2 feet. Find the perimeter of the pool.​

Answers

Answer:

48w +2

Step-by-step explanation:

Perimeter of a rectangle=2( length+width)

=2(15w-1+9w+2)

=2(24w+1)

=48w+2

Write two different polynomials with a difference of
- 3x² + 5x - 7​

Answers

Answer:

(-5 +/- i√59)/-6

Step-by-step explanation:

(-5 +/- √25-84)/2(-3)

(-5 +/- i√59)/-6

How do you graph y=2/3x-4

Answers

━━━━━━━☆☆━━━━━━━

▹ Answer

You can use a graphing calculator.

▹ Step-by-Step Explanation

Attached is a screenshot.

Hope this helps!

CloutAnswers ❁

━━━━━━━☆☆━━━━━━━

Answer:

See explanation and picture attached

Step-by-step explanation:

We can break down this expression into it's core components:

Since the constant here is -4, the y intercept is -4.

Since the value we are multiplying x by is [tex]\frac{2}{3}[/tex], the slope is  [tex]\frac{2}{3}[/tex]. This means for every time we go horizontal 3 units, the line increases by 2.

The graph is attached.

Hope this helped!

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