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3 years ago

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Helene claimed that the expected value when rolling a fair die was 3.5. Steve said that wasn't possible. He said that the expect

ed value was the most likely value in a single roll of the die, and since it wasn't possible for a die to turn up with a value of 3.5, the expected value couldn't possibly be 3.5. Who is right

1 answer:

Nesterboy [21]3 years ago

4 0

Answer:

Helene is right

Step-by-step explanation:

Mathematically, the expected values is defined as the sum of all the possible outcomes that an event can have times the probality of the respective outcome:

x = ∑ p *i,

where x is the expected value, i represents every outcome that can occur, and p is the probability of said outcome.

Now, for the case of a dice, the expected value would be:

x = 1 * $\frac{1}{6}$ + 2 * $\frac{1}{6}$ + 3 * $\frac{1}{6}$ + 4 * $\frac{1}{6}$ + 5* $\frac{1}{6}$ + 6 * $\frac{1}{6}$ ,

as every outcome has the same chance of happenning. Solving we get that:

x= $\frac{1}{6}$ *(1 +2 +3 +4+5+6) = $\frac{1}{6}$ * 21 = 3.5

Helene is right.

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Consider the equation below. (If you need to use -[infinity] or [infinity], enter -INFINITY or INFINITY.)f(x) = 2x3 + 3x2 − 180x

soldier1979 [14.2K]

Answer:

(a) The function is increasing $\left(-\infty, -6\right) \cup \left(5, \infty\right)$ and decreasing $\left(-6, 5\right)$

(b) The local minimum is x = 5 and the maximum is x = -6

(c) The inflection point is $x = -\frac{1}{2}$

(d) The function is concave upward on $\left(- \frac{1}{2}, \infty\right)$ and concave downward on $\left(-\infty, - \frac{1}{2}\right)$

Step-by-step explanation:

(a) To find the intervals where $f(x) = 2x^3 + 3x^2 -180x$ is increasing or decreasing you must:

1. Differentiate the function

$\frac{d}{dx}f(x) =\frac{d}{dx}(2x^3 + 3x^2 -180x) \\\\\mathrm{Apply\:the\:Sum/Difference\:Rule}:\quad \left(f\pm g\right)'=f\:'\pm g'\\\\f'(x)=\frac{d}{dx}\left(2x^3\right)+\frac{d}{dx}\left(3x^2\right)-\frac{d}{dx}\left(180x\right)\\\\f'(x) =6x^2+6x-180$

2. Now we want to find the intervals where f'(x) is positive or negative. This is done using critical points, which are the points where f'(x) is either 0 or undefined.

$f'(x) =6x^2+6x-180 =0\\\\6x^2+6x-180 = 6\left(x-5\right)\left(x+6\right)=0\\\\x=5,\:x=-6$

These points divide the number line into three intervals:

$(-\infty,-6)$ , $(-6,5)$ , and $(5, \infty)$

Evaluate f'(x) at each interval to see if it's positive or negative on that interval.

$\left\begin{array}{cccc}Interval&x-value&f'(x)&Verdict\\(-\infty,-6)&-7&72&Increasing\\(-6,5)&0&-180&Decreasing\\(5, \infty)&6&72&Increasing\end{array}\right$

Therefore f(x) is increasing $\left(-\infty, -6\right) \cup \left(5, \infty\right)$ and decreasing $\left(-6, 5\right)$

(b) Now that we know the intervals where f(x) increases or decreases, we can find its extremum points. An extremum point would be a point where f(x) is defined and f'(x) changes signs.

We know that:

f(x) increases before x = -6, decreases after it, and is defined at x = -6. So f(x) has a relative maximum point at x = -6.

f(x) decreases before x = 5, increases after it, and is defined at x = 5. So f(x) has a relative minimum point at x = 5.

(c)-(d) An Inflection Point is where a curve changes from Concave upward to Concave downward (or vice versa).

Concave upward is when the slope increases and concave downward is when the slope decreases.

To find the inflection points of f(x), we need to use the f''(x)

$f''(x)=\frac{d}{dx}\left(6x^2+6x-180\right)\\\\\mathrm{Apply\:the\:Sum/Difference\:Rule}:\quad \left(f\pm g\right)'=f\:'\pm g'\\\\f''(x)=\frac{d}{dx}\left(6x^2\right)+\frac{d}{dx}\left(6x\right)-\frac{d}{dx}\left(180\right)\\\\f''(x) =12x+6$

We set f''(x) = 0

$f''(x) =12x+6 =0\\\\x=-\frac{1}{2}$

Analyzing concavity, we get

$\left\begin{array}{cccc}Interval&x-value&f''(x)\\(-\infty,-1/2)&-2&-18\\(-1/2,\infty)&0&6\\\end{array}\right$

The function is concave upward on $(-1/2,\infty)$ because the f''(x) > 0 and concave downward on $(-\infty,-1/2)$ because the f''(x) < 0.

f(x) is concave down before $x = -\frac{1}{2}$ , concave up after it. So f(x) has an inflection point at $x = -\frac{1}{2}$ .

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3 years ago

What is 7/12 as a decimal<br><br> Please help ASAP

svlad2 [7]

Answer:

$\frac{7}{12} = 0.583333333...$

Step-by-step explanation:

To write $\frac{7}{12}$ as a decimal.

Decimal defined as the number with a decimal point in it.

also, the decimal point separates part of whole number and the fractional part in the decimal numbers.

To turn this fraction into a decimal number,

all you have to do is to divide the top number by bottom number i.e

$\frac{7}{12} = 7 \div 12$

$\frac{7}{12} = 0.583333333...$

Therefore, 7/12 as a decimal is, 0.583333333....

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12. It takes Daphne 25 minutes to assemble a model plane. During her work

ziro4ka [17]

Answer:

25p+45 < 480

Step-by-step explanation:

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2 years ago

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AlladinOne [14]

Answer: 10 m/s^2

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100/10 = 10

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3 years ago

(X+5)+(x-5)=56 what does x=?

kirill115 [55]

Answer:

x=28

Step-by-step explanation:

Step 1: Simplify both sides of the equation.

x+5+x−5=56

x+5+x+−5=56

(x+x)+(5+−5)=56(Combine Like Terms)

2x=56

2x=56

Step 2: Divide both sides by 2.

2x/2=56/2

x=28

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