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Bingel [31]
2 years ago
12

How to express cos 3x in terms of cosx

Mathematics
1 answer:
Elena-2011 [213]2 years ago
5 0
\cos3x=\cos(x+2x)=\cos x\cos2x-\sin x\sin2x
=\cos x(\cos^2x-\sin^2x)-2\sin^2x\cos x
=\cos^3x-\cos x\sin^2x-2\sin^2x\cos x
=\cos^3x-3\cos x\sin^2x
=\cos^3x-3\cos x(1-\cos^2x)
=\cos^3x+3\cos^3x-3\cos x
=4\cos^3x-3\cos x
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In August 2003, 56% of employed adults in the United States reported that basic mathematical skills were critical or very import
Serga [27]

Answer:

Yes

Step-by-step explanation:

First, suppose that nothing has changed, and possibility p is still 0.56. It's our null hypothesis. Now, we've got Bernoulli distribution, but 30 is big enough to consider Gaussian distribution instead.

It has mean μ= np =  30×0.56=16.8

standard deviation s = √npq

sqrt(30×0.56×(1-0.56)) = 2.71

So 21 is (21-16.8)/2.71 = 1.5494 standard deviations above the mean. So the level increased with a ˜ 0.005 level of significance, and there is sufficient evidence.

7 0
2 years ago
A teacher has 100 chairs to arrange for an assembly into equal rows Write one way the chairs could be arranged Include the numbe
tiny-mole [99]
That's easy if there is 100 chairs there would be 10 rows with ten chairs in each row
3 0
3 years ago
Read 2 more answers
The slope of the line in the graph is
gizmo_the_mogwai [7]

Answer:

the slope of the line in the graph is: 3

the y-intercept is: -4

the equation of the line is: y=3x-4

Step-by-step explanation:

If we find a point on the graph and count it until it reaches other solid point we get that you have to go up three and to the right by one. This solid point I looked at was (0,-4) and counted up to (-1,1). To find the slope, we have to simply count and use "rise over run". The rise is 3 for every 1 we run, making the slope 3/1 which is 3.

the y-intercept is the point on the graph that touches the y-axis on the graph. The only point on the graph that touches the y-axis is -4, making the y-intercept -4.

The equation for a graph is y=mx+b. m would be the slope and b would be the y-intercept. We know that the slope is 3 (m) and that the y-intercept is -4 (b). Putting them together, we get that the equation of the graph is y=3x-4.

6 0
2 years ago
0.2 ✕ -0.5 ✕ ( -0.9- -0.7)
Luba_88 [7]

Answer:

0.02

Step-by-step explanation:

0.2\times -0.5\times (-0.9 - -0.7)= \\\\0.2\times -0.5 \times (-0.2)= \\\\0.02

Hope this helps!

4 0
3 years ago
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Pls help and show work! giving brainliest and thanks :)
VLD [36.1K]

Answer:

Step-by-step explanation:

mean : added up the values and divide the result by the number of the values

Mr Jones = (5 + 6.25 + 5.75 + 6.50 + 8)/5 = $6.30

Mrs Jones = (5.50 + 7 + 6.25 + 5.75 + 7.75)/5 = $6.45

The difference between the two mean is 15 cents or $0.15

4 0
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