All categories

3 years ago

Which expression is equivalent to \sqrt(-80)?

2 answers:

8 0

√-80 can be factored out, to see which factors can be square rooted. A pair of factors would be 16 and -5, so that would be 4√-5. But, negative numbers cannot be inside a square root. So, √-1 is the same thing as i, or imaginary number. So, the expression equivalent to √-80 is 4i√5.
Have a nice day! ♪

zysi [14]3 years ago

4 0

C on 3dgenuity just took quiz.

You might be interested in

Express 0.7033 as a mixed number

viva [34]

We can make 0.7033 an improper fraction by multiplying it by 10,000 to get:

7033/10,000

Note that this cannot be a mixed number because 10,000, the denominator, is greater than 7033, the numerator.

You may have misspelled or typoed the question, or the question might be wrong, because 0.7033 can't be written as a mixed number.

7 0

3 years ago

<img src="https://tex.z-dn.net/?f=cos%20%5B%20arctan%28%5Cfrac%7B12%7D%7B5%7D%29%20-%20arcsin%20%28%5Cfrac%7B-3%7D%7B5%7D%29%5D"

qwelly [4]

Answer: -16/65

Step-by-step explanation:

Drawing the right triangle (as attached) gives us that $\arctan \left(\frac{12}{5} \right)=\arcsin \left(\frac{12}{13} \right)$

Also, $-\arcsin \left(-\frac{3}{5} \right)=\arcsin \left(\frac{3}{5} \right)$

This means our original expression is equal to:

$\cos \left[\arcsin \left(\frac{12}{13} \right)+\arcsin \left(\frac{3}{5} \right) \right]$

Using the cosine addition formula, which states $\cos(a+b)=\cos a \cos b-\sin a \sin b$ , we get this itself is equal to:

$\cos \left(\arcsin \left(\frac{12}{13} \right) \right)\cos \left(\arcsin \left(\frac{3}{5} \right)\right)-\sin \left(\arcsin \left(\frac{12}{13} \right) \right)\sin \left(\arcsin \left(\frac{3}{5} \right)\right)$

Since $\sin^{2} \theta+\cos^{2} \theta=1$ , we know that:

$\sin^{2} \left(\arcsin \left(\frac{12}{13} \right)\right)+\cos^{2} \left(\arcsin \left(\frac{12}{13} \right)\right)=1\\\\\frac{144}{169} +\cos^{2} \left(\arcsin \left(\frac{12}{13} \right)\right)=1\\\\cos^{2} \left(\arcsin \left(\frac{12}{13} \right)\right)=\frac{25}{169}\\\\cos \left(\arcsin \left(\frac{12}{13} \right)\right)=\frac{5}{13}$

Similarly, cos(arcsin(3/5))=4/5.

This means the given expression is equal to:

$\left(\frac{5}{13} \right) \left(\frac{4}{5} \right)-\left(\frac{12}{13} \right) \left(\frac{3}{5} \right)\\\\\frac{20}{65}-\frac{36}{65}=\boxed{-\frac{16}{65}}$

3 0

2 years ago

A regression was run to determine if there is a relationship between the happiness index (y) and life expectancy in years of a g

Natasha2012 [34]

Answer:

(A) $y=-0.762+0.119x$

(B) If a country increases its life expectancy, the happiness index will increase.

(C) If the life expectancy is increased by 3.5 years in a certain country, the happiness index will increase by 0.4165.

(D) If the life expectancy is 67 years in a certain country, the happiness index will be 7.21.

Step-by-step explanation:

A regression analysis was performed to determine if there is a relationship between the happiness index (y) and life expectancy in years of a given country (x).

The output of the regression analysis are as follows:

a = -0.762

b = 0.119

r² = 0.8649

r = 0.93

(A)

The equation of the Least Squares Regression line of the form y = _ + _ x is:

$y=-0.762+0.119x$

(B)

The correction between the variables happiness index (y) and life expectancy in years of a given country (x) is, 0.93.

The correlation coefficient is positive. This implies that there is a positive relation between the two variables, i.e. as the value of life expectancy in years increases the happiness index also increases.

Thus, if a country increases its life expectancy, the happiness index will increase.

(C)

Compute the value of y for x = x + 3.5 as follows:

$y=-0.762+0.119x$

$=-0.762+0.119\times (x+3.5)\\\\=(-0.762+0.119x)+0.4165\\\\=y+0.4165$

Thus, if the life expectancy is increased by 3.5 years in a certain country, the happiness index will increase by 0.4165.

(D)

Compute the value of y for x = 67 as follows:

$y=-0.762+0.119x$

$=-0.762+0.119\times 67\\\\=-0.762+7.973\\\\=7.211\\\\\approx 7.21$

Thus, if the life expectancy is 67 years in a certain country, the happiness index will be 7.21.

6 0

4 years ago

The weights of a pack of chewing gum for a certain brand have a mean of 47.1 grams and a standard deviation of

frozen [14]

Answer:

54.6 grams

Step-by-step explanation:

https://quizlet.com/530747948/statistics-unit-2-the-normal-distribution-test-review-flash-cards/

5 0

3 years ago

Mr. Scott had $90 to spend at the hockey game. He spent 31/45 on his ticket. Then he spent 3/7 of his remaining money at the con

postnew [5]

31/45 of 90 leaves him with 62. 3/7 of 62 makes 26.5 so yes he have money left to buy the hat

7 0

3 years ago