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2 years ago

Use Descartes’s rule of signs to determine the possible number of positive and negative real zeros of f(x)=8x^4-6x^3-4x^2-7x+3

1 answer:

5 0

let's recall Descartes rule of signs, to get the Real Positive ones we start by checking the sign changes for f(x), and to get the Real Negative ones we check the sign changes for f( -x ).

Check the picture below.

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An observer (O) is located 500 feet from a school (S). The observer notices a bird (B) flying at a 39° angle of elevation from h

Serhud [2]

Answer:

h=404.89

Step-by-step explanation:

We are looking for side h, which is opposite of the observer. We know that the side adjacent to the observer is 500 feet. We also know that the angle from the observer to the bird is 39°. Because we have these values, SOH CAH TOA tells us that we should use tangent, opposite over adjacent.

We can set up our equation as follows:

tan(39°)=h/500

We can then solve for h:

500*tan(39°)=h

h=404.89

4 0

2 years ago

Find the sum of the following infinite geometric series, if it exists. 2 + 6 + 18 + 54 +… Does not exist 23,567 25,982 29,034

Sladkaya [172]

Option A: The sum for the infinite geometric series does not exist

Explanation:

The given series is $2+6+18+54+.......$

We need to determine the sum for the infinite geometric series.

<u>Common ratio:</u>

The common difference for the given infinite series is given by

$r=\frac{6}{2}=3$

Thus, the common difference is $r=3$

<u>Sum of the infinite series:</u>

The sum of the infinite series can be determined using the formula,

$S_{\infty}=\frac{a}{1-r}$ where $0$

Since, the value of r is 3 and the value of r does not lie in the limit $0$

Hence, the sum for the given infinite geometric series does not exist.

Therefore, Option A is the correct answer.

8 0

3 years ago

A normally distributed random variable with mean 4.5 and standard deviation 7.6 is sampled to get two independent values, X1 and

mr Goodwill [35]

Answer:

Bias for the estimator = -0.56

Mean Square Error for the estimator = 6.6311

Step-by-step explanation:

Given - A normally distributed random variable with mean 4.5 and standard deviation 7.6 is sampled to get two independent values, X1 and X2. The mean is estimated using the formula (3X1 + 4X2)/8.

To find - Determine the bias and the mean squared error for this estimator of the mean.

Proof -

Let us denote

X be a random variable such that X ~ N(mean = 4.5, SD = 7.6)

Now,

An estimate of mean, μ is suggested as

$\mu = \frac{3X_{1} + 4X_{2} }{8}$