Which of the following are identities? Check all that apply.
A. sin(x+y)+ sin(x - y) = 2cos x siny
B. cos(x + y) + cos(x- y) = 2cos x cosy
C. tan(x - 2) = tan x
D. COS(x + y) - cos(x - y) = 2 cos xcosy

Answer: [tex]2tan(theta)[/tex]

Step-by-step explanation:

I know this is pre-calculus, but I want to let you know what this is actually used for in real calculus. This is a method of integration called "u-substitution" which tranforms the function of 'x' into a function of 'theta'. If we allow the value of 'x' to equal 2sec(theta), we can plug this into the function to get:

[tex]\sqrt{x^2-4} =\sqrt{(2sec(theta)^2-4} =\sqrt{4sec^2(theta)-4}[/tex]

Factor out a 4 to get:

[tex]\sqrt{4(sec^2(theta)-1)}[/tex]

Take the square root of 4 to get a 2 on the outside of the radical:

[tex]\sqrt{4(sec^2(theta)-1)}=2\sqrt{sec^2(theta)-1}[/tex]

Use the trig identity below to convert the secant to tangent:

[tex]tan^2(theta)+1=sec^2(theta)[/tex]

[tex]tan^2(theta)=sec^2(theta)-1[/tex]

Therefore our expression becomes:

[tex]2\sqrt{sec^2(theta)-1}=2\sqrt{tan^2(theta)}[/tex]

The square root of tangent is simply tangent:

[tex]2\sqrt{tan^2(theta)} =2tan(theta)[/tex]

Answer:

19.8

Step-by-step explanation:

Subtract 130.2 by 110.4

Answer:

huh

Step-by-step explanation:

Answer:

the answer is C. 0.26

Step-by-step explanation:

Because 0.50 + 0.24 is 0.74 and I'm guessing it goes to 1.0

So you subtract 1.0 from 0.74 to get 0.26

Answer:

so x=5 and y= 8

Step-by-step explanation:

[tex]y = 3x - 7 \: \\ 20 = - 4x +5y \\ 20 = - 4x + 5(3x - 7) \\ 20 = - 4x + 15x - 35 \\ 20 + 35 = 11x \\ 55 = 11x \\ x = 5 \\ now \: you \: put \: x = 5 \: into \: the first \: equation \: \\ 5 \\ y = 3(5) - 7 \\ y = 8[/tex]

0 3 6 9 12 15 18

(each tick mark = +3)

Check the picture below.

[tex]\stackrel{X}{1\frac{1}{2}}~~ + ~~\stackrel{X}{1\frac{3}{4}}~~ + ~~\stackrel{X}{1\frac{3}{4}} \\\\[-0.35em] ~\dotfill[/tex]

[tex]\stackrel{mixed}{1\frac{1}{2}}\implies \cfrac{1\cdot 2+1}{2}\implies \stackrel{improper}{\cfrac{3}{2}} ~\hfill \stackrel{mixed}{1\frac{3}{4}}\implies \cfrac{1\cdot 4+3}{4}\implies \stackrel{improper}{\cfrac{7}{4}} \\\\[-0.35em] ~\dotfill\\\\ \cfrac{3}{2}~~ + ~~\cfrac{7}{4}~~ + ~~\cfrac{7}{4}\implies \cfrac{(2)3~~ + ~~(1)7~~ + ~~(1)7}{\underset{\textit{using this LCD}}{4}}\implies \cfrac{20}{4}\implies 5[/tex]

Answer:

So first you have to make all the denominaters (bottom #s) the same so we would get 12/20-8/20+5/20 and you would solve this to equal 9/20 and to divide it by 1/6 would equal 2 7/10.

Hope this helps! (pls read the comment for free gift cards)

The true statements are m + 2.1 > n + 2.1, m - (-4) > n - (-4) and 9 + m > 6 + n

The inequality is given as:

m > n

When the same constant k is added to both sides of the inequality, we have:

m + k > n + k

This means that the following inequality is true

m + 2.1 > n + 2.1

When the same constant k is subtracted from both sides of the inequality, we have:

m - k > n - k

This means that the following inequality is true

m - (-4) > n - (-4)

Also, if a greater constant is added to m, then the inequality still remains the same.

This means that the following inequality is true

9 + m > 6 + n

Hence, the true statements are m + 2.1 > n + 2.1, m - (-4) > n - (-4) and 9 + m > 6 + n

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Answer:

It´s actually A, B, D

Step-by-step explanation:

Answer:

Step-by-step explanation:

Solve each inequality in the system:

The solution is:

The integer solution set is:

[tex]\\ \rm\rightarrowtail 3-2a<13[/tex]

[tex]\\ \rm\rightarrowtail -2a<10[/tex]

[tex]\\ \rm\rightarrowtail -a<5[/tex]

[tex]\\ \rm\rightarrowtail a>-5[/tex]

And

[tex]\\ \rm\rightarrowtail 5a<17[/tex]

[tex]\\ \rm\rightarrowtail a<17/5[/tex]

[tex]\\ \rm\rightarrowtail a<3\dfrac{2}{5}[/tex]

So

solution set

[tex]\\ \rm\rightarrowtail a\in\left(-5,3\dfrac{2}{5}\right)[/tex]

So

Answer:

The answer is the 2nd 1

Step-by-step explanation:

It's a basic graph

Answer:

Quadrant IV

Step-by-step explanation:

You can easily find in which quadrant a point lies using this key :

We have the coordinate (4, -5)

Answer:

Quadrant IV

Step-by-step explanation:

The Cartesian plane is divided into 4 quadrants.

Quadrant I is the top right quadrant, where x and y are positive.

We then move in a counterclockwise direction for quadrants II, III and IV.

Therefore:

As point (4, -5) has a positive x-value and a negative y-value, it will lie in Quadrant IV

Answer:

yes ur on track

Step-by-step explanation:

Answer:

0.9%

Step-by-step explanation:

I took the test

Answer:

Step-by-step explanation:

Let O be the centre of the circle of radii 10 cm and 8 cm.

In given figure,

AP = PB and OP⊥AB

Applying Pythagoras theorem in ∆OPA, we get

↠ OA² = OP² + AP²

↠ (10)² = (8)² + AP²

↠ 100 = 64 + AP²

↠ 100 - 64 = AP²

↠ 36 = AP²

↠ √36 = AP

↠ 6 = AP

Now,

↠ AB = 2AP

↠ AB = 2(6)

↠ AB = 12 cm

Hence,

Answer:

1. 6/10 – 2/5 =

Ans: 2/10, which can be reduced to 1/5.

2. If a tank is 5/8 filled with solution, how much of the tank is empty?

Ans: 3/8 of the tank is empty. Since the whole tank would equal 8/8, or 1, and 5/8 of it is filled, then that

means 3/8 of it remains empty.

3. 1/2 x 3/5 x2/3 =

Ans: 6/30, which can be reduced to 1/5.

4. 5/9 ÷ 4/11 =

Ans: 55/36. You cannot reduce this fraction any further.

5. Convert 27/4 to a decimal.

Ans: 6.75. This answer is arrived at by dividing 4 into 27.

6. Convert 0.45 to a fraction.

Ans: 45/100, which can be reduced to 9/20.

7. 4.27 x 1.6 =

Ans: 6.832

8. 6.5 ÷ 0.8 =

Ans: 8.125

9. 12 + 4.52 + 245.621 =

Ans: 262.141

Step-by-step explanation:

I hope this helps

Answer:

60 times.

Step-by-step explanation:

Prob( of rolling  a 2) = 1/6

Prob( of rolling  a 3) = 1/6

So Prob( 2 or 3) = 1/6 + 1/6 = 1/3,

So the prediction is 1/3 * 180 = 60.

Answer:

the answer is 42

Step-by-step explanation:

you multiply the sides to get the area

Answer:

[tex] \frac{x}{3} + 10 = \frac{3x - 8}{2} \\ \\ \frac{3x - 8}{2} - \frac{x}{3} = 10 \\ \\ taking \: lcm \\ \\ \frac{9x - 24 - 2x}{6} = 10 \\ \\ 9x - 24 - 2x = 60 \\ \\ 7x = 60 + 24 \\ \\ 7x = 84 \\ \\ x = \cancel\frac{84}{7} \\ \\\fbox{ x = 12}[/tex]

hope helpful ~

Answer:

[tex]x = 12[/tex]

Step-by-step explanation:

[tex] \frac{x + 30}{3} = \frac{3x - 8}{2} [/tex]

[tex]2x + 60 = 9x - 24[/tex]

[tex]60 + 24 = 9x - 2x[/tex]

[tex]84 = 7x[/tex]

[tex]x = 12[/tex]

I hope it will be helpful

Answer:

20/9

Step-by-step explanation:

2/1–>20/10 x 10/9

200/90 / 10

20/9

Hope that helps. :)

[tex]2 \div \frac{9}{10} [/tex]

[tex] \frac{2}{1} \div \frac{9}{10} [/tex]

[tex] = \frac{2}{1} \times \frac{10}{9} [/tex]

[tex] = \frac{2 \times 10}{1 \times 9} [/tex]

[tex] = \frac{20}{9} or2 \frac{2}{9} [/tex]

16x²+ 4y² = 16 is an equation of ellipse, domain of the equation is all real numbers and the range is -2 ≤ y ≤ 2.

A conic section, conic or a quadratic curve is a curve obtained from a cone's surface intersecting a plane.

The given equation is 16x²+ 4y² = 16.

Divide both sides by 16.

x²/1 + y²/4 = 1

This is the equation of an ellipse.

It is an ellipse centered at the origin, with semi-major axis length of 2 and semi-minor axis length of 1.

Since the x² term is not negative, the domain is all real numbers.

The range of the ellipse is the range of y-values that make the equation true.

Since the y² term is not negative, the range is all real numbers as well. However, since the ellipse is centered at the origin, the range is bounded by -2 and 2, which are the y-coordinates of the endpoints of the major axis. Therefore, the range is -2 ≤ y ≤ 2.

Hence, 16x²+ 4y² = 16 is an equation of ellipse, domain of the equation is all real numbers and the range is -2 ≤ y ≤ 2.

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Answer:

ellipse; Domain: {-1≤y≤1}; Range: {-2≤y≤2}

Step-by-step explanation:

Graph the equation. An ellipse has two lines of symmetry, the x-axis, and the y-axis. The domain is the set of all real numbers with x, written as -a ≤ x ≤ a. The range is the set of all real numbers with y, written as -b ≤ y ≤ b.

Answer:

The study, The Nature of Americans National Report, found that more than half of adults reported spending five hours or less in nature each week, and being satisfied with this small amount of time spent outdoors.

Step-by-step explanation:

The margin of error in the report is 2.39.

The margin of error is a statistic that describes how much random sampling error there is in survey data.

Given that, the upper interval is 24.96 and the lower interval is 20.18.

The margin of error is half of the difference between the upper and the lower interval.

Therefore, the margin of error is:

Margin of error = (24.96 - 20.18)/2

                        = 4.78/2

                        = 2.39

Hence, the margin of error in the report is 2.39.

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Answer:

The transformation will be 5

Step-by-step explanation:

Answer:

See below.

Step-by-step explanation:

5x^2 + 55x + 140  ---> required

Coefficients a=5, b=55, c=140 yield

[tex]h=\frac{-h}{2*a} =\frac{-(55)}{2*5} =\frac{-55}{10} =-5.5[/tex]

Thus, the x-coordinate of the vertex is [tex]\boxed{h = -5.5 }[/tex]

Plugging x=-5.5 into the given equation yields:

[tex]k=5*(-5.5)^{2} +55*-5.5+140=-11.25[/tex]

Thus, the y-coordinate of the vertex is [tex]\boxed{k = -11.25 }[/tex]

Altogether, the vertex of the given parabola is

[tex]\boxed{ (h,k)=(-5.5,-11.25) }[/tex]

Plugging (h,k)=(−5.5,−11.25) into the vertex formula

[tex]\boxed{ y=(x-h)^2+k }[/tex]

yields the vertex form of the parabola

[tex]\boxed{ y=(x+5.5)^2-11.25 }[/tex]

Answer:

It might be a two degree angle! :)

Step-by-step explanation:

Answer:

1309 marbles

Step-by-step explanation:

All together:

Sure!

The hundredths place is the second in a decimal.

with rounding, if the number is greater than or equal to 5, you round up, if not, you round down.

In this case we round up because 9 is bigger than 5.

So, it becomes 6.79

Therefore your answer is B

Answer:

20 minutes, or 1/3 hour

Step-by-step explanation:

Donnie travels at 9 miles/hr.  

The relationship between speed, distance, and time is Time = Distance/Speed.  [from Distance = Speed*Time]

Time to bike 3 miles at 9 miles/hr is = (3 miles)/(9 miles/hr) = (1/3) hr

It took 1/3 hour, or 20 minutes, to bike the three miles, with no stops for soda and hot dog.