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Nutka1998 [239]
3 years ago
12

Cos^2 2x−cos^2 6x=sin4x sin8x please help me prove it

Mathematics
1 answer:
Olin [163]3 years ago
4 0
Cos² 2x = (1+cos 4x )/2
cos² 6x  = (1+cos 12x)/2
subtract to get  1/2 (cos 4x - cos 12x )   
=  1/2 (2 sin  4x sin 8x )       as cos A - cos B =  2 [ sin (A+B)/2  sin (A-B)/2 ]
so the answer
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£40 is divided between Jim, Krutika & Natasha so that Jim gets twice as much as Krutika, and Krutika gets three times as muc
harkovskaia [24]

Answer:Jim gets £24

Step-by-step explanation:

Let the amount Natasha gets be represented as x

SO that Krutika getting  three times as much as Natasha be represented as 3x

AND Jim getting  twice as much as Krutika  be represented as 2 x 3x=6x

The equation to show how much each gets can be represented as

x + 3x  +6x=40

Solving

x +3x + 6x=40

10x =40

x =40/10 =4

Natasha gets £4

Krutika gets 3x =3x4= £12

Jim gets 6x=6 x4= £24

7 0
3 years ago
The change in water level of a lake is modeled by a polynomial function, W(x). Describe how to find the x-intercepts of W(x) and
Agata [3.3K]
<span>First. <u>Finding the x-intercepts of </u>W(x)
</span><span>
Let W(x) be the change in water level. So to find the x-intercepts of this function we can use The Rational Zero Test that states:

To find the zeros of the polynomial:

f(x)=a_{n}x^{n}+a_{n-1}x^{n-1}+...+a_{2}x^{2}+a_{1}x+a_{0}

We use the Trial-and-Error Method which states that a factor of the constant term:

a_{0}

can be a zero of a polynomial (the x-intercepts).

So let's use an example: Suppose you have the following polynomial:

W(x)=x^{4}-x^{3}-7x^{2}+x+6

where the constant term is a_{0}=6. The possible zeros are the factors of this term, that is:

1, -1, 2, -2, 3, -3, 6 \ and \ -6.

Thus:

</span>W(1)=0 \\ W(-1)=0 \\ W(2)=-12 \\ W(-2)=0 \\ W(3)=0 \\ W(-3)=48 \\ W(6)=840 \\ W(-6)=1260<span>

From the foregoing, we can affirm that 1, -1, -2 \ and \ 3 are zeros of the polynomial.

</span>Second. <u>Construction a rough graph of</u> W(x)

Given that this is a polynomial, then the function is continuous. To graph it we set the roots on the coordinate system. We take the interval:

[-2,-1]

and compute W(c) where c is a real number between -2 and -1. If W(c)>0, the curve start rising, if not, the curve start falling. For instance:

If \ c=-\frac{3}{2} \\ \\ then \ w(-\frac{3}{2})=-2.81

Therefore the curve start falling and it goes up and down until x=3 and from this point it rises without a bound as shown in the figure below


7 0
3 years ago
Read 2 more answers
The domain of u(x) is the set of all real values except 0 and the domain of v(x) is the set of all real values except 2. What
Oksana_A [137]

Using the domain concept, the restrictions on the domain of (u.v)(x) are given by:

A. u(x) ≠ 0 and v(x) ≠ 2.

<h3>What is the domain of a data-set?</h3>

The domain of a data-set is the set that contains all possible input values for the data-set.

To calculate u(x) x v(x) = (u.v)(x), we calculate the values of u and v and then multiply them, hence the restrictions for each have to be considered, which means that statement A is correct.

Summarizing, u cannot be calculated at x = 0, v cannot be calculated at x = 2, hence uv cannot be calculated for either x = 0 and x = 2.

More can be learned about the domain of a data-set at brainly.com/question/24374080

#SPJ1

3 0
2 years ago
1) What is 20% of 20?<br> 2) what is 15 is what percent of 30?<br> 3) 50 is 50% of what?
N76 [4]

Hi there!

The word "of" is the same thing as a multiplication sign.

1)

20% = 0.2

0.2 × 20 = 4


2)

? × 30 = 15

divide each side of the equation by 30

? = 0.5

0.5 = 50%


3)

50% = 0.5

0.5 × ? = 50

divide each side of the equation by 0.5

? = 100


There you go! I really hope this helped, if there's anything just let me know! :)

7 0
3 years ago
Read 2 more answers
Geometry help please. Answer choices: A, B, C, or d. Picture beloe.
ira [324]

Answer:

D

Step-by-step explanation:

you reverse the numbers in the y spot, so if they are negative make them positive, vise versa

8 0
3 years ago
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