Rút gọn các biểu thức sau:
a,√3-2√2
b,√4-2√3
c,√8-2√7
d,√7-4√3
e,√11-6√2
(Tất cả các căn đều không cách)

Answer:

Step-by-step explanation:

[tex]3=\frac{a+r}{a-r} \\3a-3r=a+r\\3a-a=r+3r\\4r=2a\\r=\frac{1}{2} a[/tex]

The Euler's formula relates the vertices, faces and the edges of a polyhedron.

The correct option is (e) [tex]V = 6[/tex]    [tex]E = 10[/tex]    [tex]F = 6[/tex]     [tex]6- 10 + 6 = 2[/tex]

First, we count the number of faces. This is the flat parts of the shape.

The attached shape has 6 flat surfaces.

So:

[tex]F = 6[/tex]

Next, we count the number of edges. This is where two faces meet.

The attached shape has 10 edges;

So:

[tex]E = 10[/tex]

Lastly, we count the number of vertices. This is where two edges meet.

The attached shape has 6 vertices.

So:

[tex]V = 6[/tex]

Using Euler's formula, we have:

[tex]V - E + F = 2[/tex]

Substitute values for V, E and F

[tex]6- 10 + 6 = 2[/tex]

[tex]2 = 2[/tex]

Hence, the polyhedron has 6 vertices, 10 edges and 6 faces

Read more vertices, edges, and faces at:

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Answer:

19.365

Step-by-step explanation:

The Pythagoreum Theorum tells us that:

a² + b² = c²

where a and b are the legs and c is the hypotenuse.

BC is a leg; we'll lable it a.

AC is the hypotenuse thus labled c.

Plugging their lengths into the above formula will solve for the missing leg length.

5² + x² = 20²

25 + x² = 400

x² = 375

✓x = ✓3 x (5 x 5) x 5

x = 5✓15

x = 19.365

Given:

The function [tex]g(x)[/tex] doubles the square of the input and then subtracts 13.

To find:

The value of [tex]g(3)[/tex].

Solution:

Let [tex]x[/tex] be the input value.

The square of the input is [tex]x^2[/tex].

Doubles the square of the input [tex]2x^2[/tex].

Doubles the square of the input and then subtracts 13, i.e., [tex]2x^2-13[/tex].

So, the function is:

[tex]g(x)=2x^2-13[/tex]

Putting [tex]x=3[/tex] in the above function, we get

[tex]g(3)=2(3)^2-13[/tex]

[tex]g(3)=2(9)-13[/tex]

[tex]g(3)=18-13[/tex]

[tex]g(3)=5[/tex]

Therefore, the value of [tex]g(3)[/tex] is 5.

Answer:

0.1294

Step-by-step explanation:

Number of chocolates in box = 38

Number of nuts = 8

Number of caramel = 16

Number of solid chocolate = 14

Since 2 are selected in a row and not replaced, then;

Probability of first being solid chocolate = 14/38

Probability of second being solid chocolate after first one = 13/37

Thus;

P(2 selected in a row being solid chocolate) = 14/38 × 13/37 = 0.1294

Answer:

120

Step-by-step explanation:

All the interior angles in a regular hexagon are 120 degrees.

Answer:

a) Sinusoidal functions are y = a sin [b(x-h)] + k    (or)                                        

y = a cos [b(x-h)] + k

Where a is amplitude a= (max-min)/2=(16-2)/2=7

period p= 2π/b

            b=2π/30

            Horizontal transformation to 10 units right h=10

            k= (max+min)/2=(16+2)/2=9

h = 7 cos [π/15(t-10)]+ 9

b) t=10min=600 sec

substitue in the above equation

h=5.5m

we observe that this figure could be divided into a triangle and a rectangle.

for the area of the triangle, bxh/2, we have 15 x 12/2 = 90

and for the rectangle, we have 5 x 12 = 60

so, 90 + 60 = 150

hope it helps :)

=====================================================

Explanation:

We can rewrite 5 as 5s^0, since s^0 = 1 where s is nonzero.

Think of 2s as 2s^1

With those ideas in mind, the original polynomial turns into 5s^0 + 2s^1

Sorting the terms so that the largest exponent is first gets us the standard form 2s^1 + 5s^0

The largest exponent is the degree, so the degree is 1.

Side note: This trick only works for single variable polynomials.

Answer:

V = 5,324 in^3

Step-by-step explanation:

V = 4([tex]\pi[/tex]r^3)/3

= 4(3)(11^3)/3

= 12(11)(11)(11)/3

= 12(1,331)/3

= 15,972/3

V = 5,324 in^3

Answer:

5575.28 or 5,324 depending on use of pie.

Step-by-step explanation

V=4/3πr3=4/3·π·113≈5575.27976

Hope this helps :)!

This is the answer if pie is used as 3.14.

V = 5,324 in^3 if pie used as 3.

V = 5575.28 in^3 if pie used as 3.14.

Answer:

the answer is correct

Step-by-step explanation:

hope u like

Answer:

2=124  124/2

4=248 248/4

5=310 310/5

8=496 496/8

Step-by-step explanation:

40 + 22 = 62

62 x 2 = 124

62 x 4 = 248

62 x 5 = 310

62 x 8 = 496

i think

Answer: x³-21x+20=0

Step-by-step explanation:

To find which polynomial has 1, 4, -5 as the roots, all we have to do is equal each root to 0 and multiply all factors together.

1 is (x-1)=0

4 is (x-4)=0

-5 is (x+5)=0

Now, we just multiply them together.

(x-1)(x-4)(x+5)=0                       [FOIL]

(x²-4x-x+4)(x+5)=0                    [combine like terms]

(x²-5x+4)(x+5)=0                      [FOIL]

x³+5x²-5x²-25x+4x+20=0       [combine like terms]

x³-21x+20=0

Now we know x³-21x+20=0 is the polynomial with those roots.

Answer:

B, pi

Step-by-step explanation:

The sine wave shown above has two waves until it reaches 2 pi, making the period of the sine graph 2pi divided by the two waves, making the answer pi.

Answer:

B: the accuracy rate of most people is barely above the 50% guessing level

Step-by-step explanation:

Bond and DePaul carried out a research and analysis on the accuracy of deception judgments in 2016.

This research involved synthesizing of results gotten from 206 research documents as well as a total of 24483 judges.

In this research and analysis, there were a couple of discoveries when people tried to discriminate lies from the truth and these discoveries include; average percentage of correct lie-truth judgments, percentage of those who correctly classified lies as deception and also percentage of those who classified truths as non-deceptive e.t.c. In conclusion, part of their discoveries was that the accuracy rate of most people is barely above the 50% guessing level.

This corresponds to option B.

Answer:

Last option= 30 minutes

The fish's length will affect the mean because the new mean length will be less than 14.2 inches. That is option A.

Mean is defined as the sum of all the data values divided by the count of values in a data set.

What a new value is added to a data set such as the group of fishes, it will affect the fish mean by reducing it to less than its former mean value which is 14.2 inches.

Therefore, the fish's length will affect the mean because the new mean length will be less than 14.2 inches.

Learn more about mean here:

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#SPJ1

Answer:

3.9

Step-by-step explanation:

We can use the Pythagorean theorem

a^2 +b^2 =c^2 where a and b are the legs and c is the hypotenuse

7^2 + h^2 = 8^2

49 + h^2 = 64

h^2 = 64-49

h^2 = 15

Taking the square root of each side

sqrt(h^2) = sqrt(15)

h = 3.87298

To the nearest tenth

h = 3.9

Answer:

x =6

Step-by-step explanation:

5(x-2) = 14+x

Distribute

5x-10 = 14+x

Subtract x from each side

5x-x -10 = 14+x-x

4x-10 = 14

Add 10 to each side

4x-10+10 = 14+10

4x= 24

Divide by 4

4x/4 = 24/4

x =6

Answer:

5(×-2)=14+×

5x-10=14+x

5x-x=14+10

4x=24

x=6

Answer:

wea did tha r come from??

Step-by-step explanation:

it is supposed to be d

Answer:

hello,

Step-by-step explanation:

[tex]cos(3\theta)+cos(4\theta)\\\\=2*cos(\dfrac{4\theta+3\theta}{2} )*cos(\dfrac{4\theta-3\theta}{2} )\\\\\boxed{=2*cos(\dfrac{7\theta}{2} )*cos(\dfrac{\theta}{2} )}[/tex]

I think you tried copy pasting the thing in here. usually written equations on tests or whatever don't copy paste well

Answer:

The 19th term is 99.

Step-by-step explanation:

We can write a direct formula and use it to find the 19th term. Recall that the direct formula for an arithmetic sequence is given by:

[tex]x_n = a + d(n-1)[/tex]

Where a is the initial term and d is the common difference.

Since the first term is 9 and the common difference is 5:

[tex]\displaystyle x _ n = 9+5(n-1)[/tex]

To find the 19th term, let n = 19. Thus:

[tex]x_{19} = 9+5(19-1)[/tex]

And evaluate:

[tex]\displaystyle \begin{aligned} x_{19} &= 9+5(18) \\ &= 9+90 \\ &= 99\end{aligned}[/tex]

The 19th term is 99.

Answer:

8 cm

Step-by-step explanation:

The length of the whole shape is 13. On the right side, it says the length is 5 cm. You use 13-5 to get the missing length.

Answer:

the answer is 8 cm

Step-by-step explanation:

Answer:

6

Step-by-step explanation:

4n - 12 < 2n + 2 is for n=6

4×6 -12 < 2×6 +2

24 - 12 < 12 + 2

12 < 14 correct

for n=7

4×7 - 12 < 2×7 + 2

16 < 16 incorrect

for n=8

4×8 - 12 < 2×8 + 2

20 < 18 incorrect

for n=9

4×9 - 12 < 2×9 + 2

24 < 20 incorrect

so, only for n=6 is the expression true.

Answer:

6

Step-by-step explanation:

4n - 12 < 2n + 2 is for n=6

4×6 -12 < 2×6 +2

24 - 12 < 12 + 2

12 < 14 correct

for n=7

4×7 - 12 < 2×7 + 2

16 < 16 incorrect

for n=8

4×8 - 12 < 2×8 + 2

20 < 18 incorrect

for n=9

4×9 - 12 < 2×9 + 2

24 < 20 incorrect

so, only for n=6 is the expression true.Step-by-step explanation:

Answer:

see below

Step-by-step explanation:

Since this is a right triangle, we can use trig functions

cos theta = adj / hypotenuse

cos x = 13/20

Taking the inverse cos of each side

arccos ( cos x ) = arccos( 13/20)

x = arccos ( 13/20)

x =49.45839

x = 49  to the nearest whole number

sin theta = opp/ hyp

sin y = 13/20

Taking the inverse sin of each side

arcsin ( sin y ) = arcsin( 13/20)

y = arcsin ( 13/20)

y=40.5416

y = 41 to the nearest whole number

Answer:

ab=9 and ac=12

Step-by-step explanation: