Find cos 2α; the angle α is in the fourth quadrant, and sin α = -0.45. Which double-angle identity should you use?


cos2α = 1 – 2〖sin〗^2α

sin(α)cos(α) - cos(α)sin(α)

sin(α)cos(α)

2sin(α)cos(α)

Answer:

24

Step-by-step explanation:

We have a system of equations, so we can start with the second equation:

[tex]x-y=2[/tex]

And move y to the other side to isolate x:

[tex]x=2+y[/tex]

Now we can replace x into the first equation:

[tex](2+y)^{2} -y^{2} =48\\ (2+y)(2+y)-y^{2} =48\\ 4+4y+y^{2} -y^{2} =48[/tex]

Notice that we can cancel out the y squared terms:

[tex]4+4y=48\\ 4y=44\\ y=11[/tex]

Now we just need to find x by replacing y into the second equation:

[tex]x-11=2\\ x=13[/tex]

And finally, add them:

[tex]x+y=11+13\\ x+y=24[/tex]

Hope this helps.

Answer:

x= 13

y=11

x^2 - y^2 = 48        and       x - y = 2

                                           x = 2 + y

(2 + y)^2 - y^2 = 48

(2 + y) (2 + y) - y^2 = 4

(4 + 2y +2y + y^2) -y^2 = 48

4 + 4y + y^2 - y^2 = 48

4 + 4y = 48

4y = 48 -4

4y = 44

y= 44/4

y= 11

Plug y back into the original equation:

x^2 - y^2 = 48

x^2 - 11^2 = 48

x^2 - 121 = 48

x^2 = 121 + 48

x^2 = 169

The square root of 169 is 13

So x= 13

x + y

13 + 11 = 24

Answer:

i think 2. division property of equality

distributive property of multiplication over addition

Answer:

3.a)2[tex]\sqrt[3]{2}[/tex]

5.a) x=2

Step-by-step explanation:

Answer:

1. If 3^x = 1 then x =0

Step-by-step explanation:

3^0 = 1

3. 2, 9 3, 7, 5, the median is 5

4.3,5,3,4,3 the mode is 3

5. A cube whose volume is 8^3 =(512cm^3)

3. B

Answer:

y=2x+10

Step-by-step explanation:

the picture has the answer

Answer:

41/5

Step-by-step explanation:

So the answer is that 8 1/5 as a decimal is 8.2.

We convert it to an improper fraction which, in this case, is 41/5 and then we divide the new numerator (41) by the denominator to get our answer.

Answer:

im not an expert in math but i'll do my best:

1. an approximation is something that is almost, but not exactly something. for example, 5.02 is approximately 5. it's not EXACTLY 5, but it's around 5.

2. decimal place refers to the position of numbers after the decimal point. let's take the decimal number 7.89 for example. there are 2 numbers after the decimal point, which is 8 and 9. hence we say that 7.89 has 2 decimal places.

3. significant figure is kind of hard to explain, so i'll jump into the example straight away.

5.874 to 3 significant figures is 5.87. what i did was count 3 digits: starting from 5 to 7. to round to 3 significant figures, i look at the 4th digit, which is 4 in this case. if it's smaller than 5, i ignore everything past the digit 7, and leave the final answer as 5.87.

if the 4th digit is greater than or equal to 5, i add 1 to the 3rd digit THEN leave out all the numbers after the 3rd digit. (if this were the case, the answer would be 5.88)

lets take a trickier example, 0.064591

in this case i cannot start counting 3 digits starting from 0. i have to count starting from the number 6. the concept in this case is that the 1st significant figure cannot be a 0. in this case the answer to 3 significant figures would be 0.0646.

however, 0 can be a significant figure if it's after another number. for instance 0.90672

the 0 after the 9 would count as a significant figure because it's not the 1st significant figure in the number. however the 0 before the 9 would NOT count as one because 0 cannot be the 1st significant figure. the answer to 3 significant figures would be 0.907.

sorry this was so lengthy, i just hope this answers your question on what these are and how they work. good luck!

Answer:

what is positive or negative???

Answer:

a) 512 cm^3

b) 469.125 cm^3

Step-by-step explanation:

8*8*8 = 512 cm^3

or

8^3 = 512 cm^3

3.5^3 = 42.875

512 - 42.875 = 469.125 cm^3

You can round the second answer down

Answer:

1

Step-by-step explanation:

1.09 is in between the whole numbers 1 and 2. it is closer to 1 since the tenths digit (0) is less than 5. if it were 5 or greater, then we would round up to 2.

Answer:

1

Step-by-step explanation:

1.09 is closer to 1 than 2, therefore the whole number is 1.

If you were counting people or objects, well you can't have 9/100 as a person so you'd round to 2. But in this case, round to 1!

I hope this helped :)

Answer:

  5, 6, 7, 8: correct

  9: the Hi.nge theorem does not apply

Step-by-step explanation:

The Hi.nge theorem says that the side opposite the angle between two pairs of congruent sides is longer if the angle is larger. This theorem is applicable to problems 5-8, and your application is correct.

__

9) The Hi.nge theorem does not apply. The marked angles are not between the congruent sides. There is no necessary relation between the marked angles and the angles that are between the congruent sides, so no conclusion can be drawn regarding the relative lengths of AB and CD.

Answer:

  36

Step-by-step explanation:

Usually, when we talk about an n-digit number, we mean one that has no leading zeros. If we use all 9 non-zero digits, the single number having increasing digits is ...

  123456789

We cannot swap any digits and have the digits remain in increasing order. The only thing we can do to create different numbers is remove different pairs of digits.

There are 9C2 = 9·8/(2·1) = 36 different ways to choose 2 digits from 9. Thus, there are 36 possible 7-digit numbers with the digits in increasing order.

__

Additional comment

The first few are 1234567, 1234568, 1234569, 1234578, 1234579, 1234589, ...

[tex]\underline\mathtt\colorbox{gold}{1 day}[/tex]

Step-by-step explanation:

1440 minutes, 24 hours or 1 day

Answer:

Yes

Step-by-step explanation:

You can answer this question by putting in the x-value [the 4 in (4, 8)] in for the x variable to see if you get the y-value [the 8 in (4, 8)] as the solution.

y=2(4)

y=8

Since 8 was the answer then yes, (4, 8) satisfies the equation y = 2x.

If asking how many 1/2 a yard(s) are in a whole yard your answer is 2, because 1/2 + 1/2 = 1

Answer:

23x + 9

 ———————

    9  

Step-by-step explanation:

x = 3y

or y = x/3

bottom line : there are three times as many x as there are y. or the number of y is 1/3 of x.

Answer: x=-3ab/2+ac

Step-by-step explanation:

Multiply to remove the fraction, then set equal to 0 and solve.

Answer:

y = -29/19  and x = -44/19

Step-by-step explanation:

3x + 2y = -10    multiply by -2  ⇔    -6x -  4y = 20

2x - 5y = 3       multiply by 3   ⇔      6x - 15y = 9    

Add the two equation                             -19y = 29

                                                                       y =  -29/19

Use equation one and solve for x

3x + 2(-29/19) = -10

3x - 58/19 = -10

3x = -10 + 58/19

3x = -190/19 + 58/19

3x = (-190 + 58)/19

  3x = -132/19

    x =  - 132/ 19 ÷3                           [tex]\frac{-132}{19} (\frac{1}{3} ) = \frac{-44}{19}[/tex]

    x =  -44/19

Answer:

Hope this helps. x

Answer:

Step-by-step explanation:

8 lbs of apples on the x-intercept

10lbs of peaches on y-intercept

Answer:

0.3

Step-by-step explanation:

hopes this helps

So the Lincoln middle school will have +5.75 pounds or ounces of ffod

Answer:

open the bracket

(4X+)-3X-2-72+X=X

4X+(-3X)-74+X=X

X-74+X=X

2X-74=X

then collect the term

-74=X-2X

-74=-X

divide by negative every side then you get

X=74

Answer:

When a dilation in the coordinate plane has the origin as the center of dilation, you can find points on the dilated image by multiplying the x- and y-coordinates of the original figure by the scale factor. For scale factor k, the algebraic representation of the dilation is (x, y) → (kx, ky). For enlargements, k > 1.

Answer:

6 13/28

Step-by-step explanation:

Hope this helps!

Step-by-step explanation:

by complete angle

x+38+52+220=360

x+310=360

x=360-310

x=50

Answer:

Pretty sure she was best known for calculating flight paths of spacecraft.

Answer:

x²y(3x - 7)(x - 3y)

Hope you could get an idea from here.

Doubt clarification - use comment section.