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zhannawk [14.2K]
2 years ago
9

How do I solve these trigonometric equations!!?

Mathematics
1 answer:
ValentinkaMS [17]2 years ago
3 0
<span>1) (sin x)(cos x) = 0 This means that either sin x = 0, or cos x = 0. Sin x = 0 when x = 0 or pi. cos x = 0 when x = pi/2 or 3pi/2. 2) cos2x + 2cosx + 1 = 0 First, expand cos2x. Simple trigonometric identity states that cos2x = (cos x)^2 - (sin x)^2.Now, substituting this equation, we get cos2x + 2cosx + 1 = (cos x)^2 - (sin x)^2 + 2cosx + 1. Note that we can now utilize the identity (cos x)^2 = 1 - (sin x)^2 to obtain (cos x)^2 + 2cosx + 1 - (sin x)^2 = 2(cos x)^2 + 2(cos x) = 0. Now, we can see that 2(cos x)^2 + 2(cos x) = 2(cos x)(cos x + 1) = 0. This is true when cos x = 0 or cos x + 1 = 0. Cos x = 0 when x = pi/2 or 3pi/2. cos x = -1 when x = pi. Therefore, x = pi/2, pi or 3pi/2.</span>
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Use the dot plot to answer the question.
Tcecarenko [31]

Answer:

Mean of the data set in the dot plot would be: 3.6

Step-by-step explanation:

As we know that Mean from the dot plot can be obtained by:

  • adding the numbers and then
  • divide the resulting sum by the number of addends.

Please check the attached figure where the dot plot is also plotted.

From the dot plot, it is clear that

There are 3 dots at 1.

There are 4 dots at 2.

There are 3 dots at 3.

There are 4 dots at 4.

There are 5 dots at 5.

There are 3 dots at 6.

All we have to do is to add the dots and divide the sum by the number of addend dots.

In other words:

There are 3 dots at 1    ⇒  1+1+1

There are 4 dots at 2   ⇒  2+2+2+2

There are 3 dots at 3   ⇒   3+3+3

There are 4 dots at 4   ⇒   4+4+4+4

There are 5 dots at 5   ⇒   5+5+5+5+5

There are 3 dots at 6   ⇒   6+6+6

As there are total 22 dots.

And the sum of all the dots with respect to their plot number = 79

i.e. 1+1+1+2+2+2+2+3+3+3+4+4+4+4+5+5+5+5+5+6+6+6 = 79

Thus

Mean of the data set in the dot plot = 79/22

                                                            = 3.6

Therefore, Mean of the data set in the dot plot would be: 3.6

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