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2 years ago

Find the indicated side of the right triangle. 60° х 7 30° x = [?] Enter

Mathematics

2 answers:

creativ13 [48]2 years ago

4 0

Answer:

Step-by-step explanation:

Mariulka [41]2 years ago

3 0

Here's the solution,

By using Trigonometry :

=》

$\sin(30) = \dfrac{7}{x}$

=》

$\dfrac{1}{2} = \dfrac{7}{x}$

=》

$x = 14$

hence, the value of x = 14 units

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"if f(x)=x+1/x then the set of values for which f increases is"

Anettt [7]

The solution for this problem would be:
f'(x) = 1 - 1/x^2 = (x^2 - 1)/x^2
is positive where |x| > 1
hence (-inf, -1) and (1, inf) are the regions in which f' is positive and therefore f is increasing.
Therefore, the answer is (-infinity,-1] U [1,infinity).

4 0

2 years ago

Easy! please help! 17% is equivalent to? A. 17/100, B. 17 to 100 C. 17:100

nika2105 [10]

The answer is a obviously

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2 years ago

Read 2 more answers

Assume that the helium porosity (in percentage) of coal samples taken from any particular seam is normally distributed with true

IgorLugansk [536]

Answer:

(a) 95% confidence interval for the true average porosity of a certain seam is [4.52 , 5.18].

(b) 98% confidence interval for the true average porosity of a another seam is [4.12 , 4.99].

Step-by-step explanation:

We are given that the helium porosity (in percentage) of coal samples taken from any particular seam is normally distributed with true standard deviation 0.75.

(a) Also, the average porosity for 20 specimens from the seam was 4.85.

Firstly, the pivotal quantity for 95% confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ ~ N(0,1)

where, $\bar X$ = sample average porosity = 4.85

$\sigma$ = population standard deviation = 0.75

n = sample of specimens = 20

$\mu$ = true average porosity

Here for constructing 95% confidence interval we have used One-sample z test statistics as we know about population standard deviation.

So, 95% confidence interval for the true mean, $\mu$ is ;

P(-1.96 < N(0,1) < 1.96) = 0.95 {As the critical value of z at 2.5% level

of significance are -1.96 & 1.96}

P(-1.96 < $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ < 1.96) = 0.95

P( $-1.96 \times {\frac{\sigma}{\sqrt{n} } }$ < ${\bar X-\mu}$ < $1.96 \times {\frac{\sigma}{\sqrt{n} } }$ ) = 0.95

P( $\bar X-1.96 \times {\frac{\sigma}{\sqrt{n} } }$ < $\mu$ < $\bar X+1.96 \times {\frac{\sigma}{\sqrt{n} } }$ ) = 0.95

95% confidence interval for $\mu$ = [ $\bar X-1.96 \times {\frac{\sigma}{\sqrt{n} } }$ , $\bar X+1.96 \times {\frac{\sigma}{\sqrt{n} } }$ ]

= [ $4.85-1.96 \times {\frac{0.75}{\sqrt{20} } }$ , $4.85+1.96 \times {\frac{0.75}{\sqrt{20} } }$ ]

= [4.52 , 5.18]

Therefore, 95% confidence interval for the true average porosity of a certain seam is [4.52 , 5.18].

(b) Now, there is another seam based on 16 specimens with a sample average porosity of 4.56.

The pivotal quantity for 98% confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ ~ N(0,1)

where, $\bar X$ = sample average porosity = 4.56

$\sigma$ = population standard deviation = 0.75

n = sample of specimens = 16

$\mu$ = true average porosity

Here for constructing 98% confidence interval we have used One-sample z test statistics as we know about population standard deviation.

So, 98% confidence interval for the true mean, $\mu$ is ;

P(-2.3263 < N(0,1) < 2.3263) = 0.98 {As the critical value of z at 1% level

of significance are -2.3263 & 2.3263}

P(-2.3263 < $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ < 2.3263) = 0.98

P( $-2.3263 \times {\frac{\sigma}{\sqrt{n} } }$ < ${\bar X-\mu}$ < $2.3263$ ) = 0.98

P( $\bar X-2.3263 \times {\frac{\sigma}{\sqrt{n} } }$ < $\mu$ < $\bar X+2.3263 \times {\frac{\sigma}{\sqrt{n} } }$ ) = 0.98

98% confidence interval for $\mu$ = [ $\bar X-2.3263 \times {\frac{\sigma}{\sqrt{n} } }$ , $\bar X+2.3263 \times {\frac{\sigma}{\sqrt{n} } }$ ]

= [ $4.56-2.3263 \times {\frac{0.75}{\sqrt{16} } }$ , $4.56+2.3263 \times {\frac{0.75}{\sqrt{16} } }$ ]

= [4.12 , 4.99]

Therefore, 98% confidence interval for the true average porosity of a another seam is [4.12 , 4.99].

7 0

2 years ago

mr. Hightower recorded the amount of each project that had been completed at the end of the week. the line plot describes the in

Citrus2011 [14]

We need a pic of the line plot to complete and answer this

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2 years ago

Write the equation of a line that is parallel to y = 7x +13 that passes through the point (28, 8).

navik [9.2K]

Answer:

y=7x-188

Step-by-step explanation:

We know that this line must have a slope of 7, because this line is parallel to y=7x+13

We must use the point slope formula: y- $y_{1}$ = m(x- $x_{1}$ )

Next, we will plug in the point (28,8) for $y_{1}$ and $x_{1}$ , and 7 in for m

y-8=7(x-28)

Solve the equation, first by distributing the 7

y-8=7x-196

Add the 8 over

y=7x-188

7 0

2 years ago