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3 years ago

Find the magnitude of angle A if cos A = 0.5

Mathematics

1 answer:

Hitman42 [59]3 years ago

4 0

Step-by-step explanation:

$A = {cos}^{ - 1} 0.5 \\ \: \: A= 60$

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Find the solution set 2x^2 -2x -4 =0 please use a comma to separate your answer.

mariarad [96]

Answer:

2,-1

Step-by-step explanation:

2x^2 -2x -4 =0

Factor out a 2

2(x^2 -x-2) =0

What 2 number multiply to -2 and add to -1

-2*1 = -2

-2 +1 = -1

2(x-2) (x+1) =0

Using the zero product property

x-2 = 0 x+1 = 0

x-2+2=0+2 x+1-1=0-1

x=2 x=-1

7 0

3 years ago

A half-century ago, the mean height of women in a particular country in their 20s was 64.7 inches. Assume that the heights of

Ainat [17]

Answer:

99.5% of all samples of 21 of today's women in their 20's have mean heights of at least 65.86 inches.

Step-by-step explanation:

We are given that a half-century ago, the mean height of women in a particular country in their 20's was 64.7 inches. Assume that the heights of today's women in their 20's are approximately normally distributed with a standard deviation of 2.07 inches.

Also, a samples of 21 of today's women in their 20's have been taken.

Let $\bar X$ = sample mean heights

The z-score probability distribution for sample mean is given by;

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

where, $\mu$ = population mean height of women = 64.7 inches

$\sigma$ = standard deviation = 2.07 inches

The Z-score measures how many standard deviations the measure is away from the mean. After finding the Z-score, we look at the z-score table and find the p-value (area) associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X.

Now, Probability that the sample of 21 of today's women in their 20's have mean heights of at least 65.86 inches is given by = P( $\bar X$ $\geq$ 65.86 inches)

P( $\bar X$ $\geq$ 65.86 inches) = P( $\frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n} } }$ $\geq$ $\frac{65.86-64.7}{\frac{2.07}{\sqrt{21} } }$ ) = P(Z $\geq$ -2.57) = P(Z $\leq$ 2.57)

= 0.99492 or 99.5%

The above probability is calculated by looking at the value of x = 2.57 in the z table which has an area of 0.99492.

Therefore, 99.5% of all samples of 21 of today's women in their 20's have mean heights of at least 65.86 inches.

3 0

3 years ago

In Mona’s new video game she earns 30 points for each fish caught and 80 points for each octopus captured, but she loses 15 poin

Aleksandr-060686 [28]

If x is fish, y is octopi, and z is crabs, then you would have to know the numbers.
Then your answer would be c. 30x+80y-15z.
Because x=+30, y=+80, and z=-15.
I hope that helps. If you need any further help on this problem just ask.

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3 years ago

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3/4 - 1/3 plz explain

balandron [24]

First covert them to fractions with the same denominator so you can compare them (9/12 and 4/12), then subtract the numerators, and not the denominators (9/12-4/12), then whatever you get is the answer (5/12). If you can, simplify.

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3 years ago

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What is the spuare root of 144

SVEN [57.7K]

Answer:

The square root of 144 will be 12

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3 years ago

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Find the magnitude of angle A if cos A = 0.5​

Find the magnitude of angle A if cos A = 0.5