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3 years ago

Y=-x+5 x-y=-9 Solve the system?

Mathematics

2 answers:

hram777 [196]3 years ago

4 0

Answer:

x=-2 y=7

Step-by-step explanation:

Oksanka [162]3 years ago

4 0

Answer:

$x=-2 \quad and \quad y=7.$

Step-by-step explanation:

$\left\{\begin{matrix} y=-x+5 \\ x-y=-9\end{matrix}\right.\\\\\Rightarrow \left\{\begin{matrix} x+y=5 & (1)\\ x-y=-9 & (2)\end{matrix}\right.\\(1) + (2) \Rightarrow 2x=-4 \Rightarrow x=-4:2=-2\\Replace \quad x=-2\quad in \quad(1) \Rightarrow y=5-(-2)=7\\Therefore, \\x=-2 \quad and \quad y=7.$

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Which definite integral approximation formula is this: the integral from a to b of f(x)dx ≈ (b-a)/n * [<img src="https://tex.z-d

Stella [2.4K]

The answer is most likely A.

The integration interval [a, b] is split up into n subintervals of equal length (so each subinterval has width (b - a)/n, same as the coefficient of the sum of y terms) and approximated by the area of n rectangles with base (b - a)/n and height y.

n subintervals require n + 1 points, with

x₀ = a

x₁ = a + (b - a)/n

x₂ = a + 2(b - a)/n

and so on up to the last point x = b. The right endpoints are x₁, x₂, … etc. and the height of each rectangle are the corresponding y 's at these endpoints. Then you get the formula as given in the photo.

• "Average rate of change" isn't really relevant here. The AROC of a function G(x) continuous* over an interval [a, b] is equal to the slope of the secant line through x = a and x = b, i.e. the value of the difference quotient

(G(b) - G(a) ) / (b - a)

If G(x) happens to be the antiderivative of a function g(x), then this is the same as the average value of g(x) on the same interval,

$g_{\rm ave}=\dfrac{G(b)-G(a)}{b-a}=\dfrac1{b-a}\displaystyle\int_a^b g(x)\,\mathrm dx$

(* I'm actually not totally sure that continuity is necessary for the AROC to exist; I've asked this question before without getting a particularly satisfying answer.)

• "Trapezoidal rule" doesn't apply here. Split up [a, b] into n subintervals of equal width (b - a)/n. Over the first subinterval, the area of a trapezoid with "bases" y₀ and y₁ and "height" (b - a)/n is

(y₀ + y₁) (b - a)/n

but y₀ is clearly missing in the sum, and also the next term in the sum would be

(y₁ + y₂) (b - a)/n

the sum of these two areas would reduce to

(b - a)/n = (y₀ + 2 y₁ + y₂)

which would mean all the terms in-between would need to be doubled as well to get

$\displaystyle\int_a^b f(x)\,\mathrm dx\approx\frac{b-a}n\left(y_0+2y_1+2y_2+\cdots+2y_{n-1}+y_n\right)$

7 0

3 years ago

Consider a value to be significantly low if its z score less than or equal to minus−2 or consider a value to be significantly hi

ziro4ka [17]

Answer:

If the weight is higher than 5.8886 gr would be considered significantly high

If the weight is lower than 5.6121 gr would be considered significantly low

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Solution to the problem

Let X the random variable that represent the weights of a population, and for this case we know the distribution for X is given by:

$X \sim N(5.75241,0.06281)$

Where $\mu=5.75241$ and $\sigma=0.06281$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\sigma}$

For the case when z =-2 we can do this:

$-2 = \frac{X-5.75241}{0.06281}$

And if we solve for X we got:

$X = 5.75241 -2*0.06281 =5.6121$

And for the other case when Z=2 we have:

$2 = \frac{X-5.75241}{0.06281}$

And if we solve for X we got:

$X = 5.75241 +2*0.06281 =5.8886$

If the weight is higher than 5.8886 gr would be considered significantly high

If the weight is lower than 5.6121 gr would be considered significantly low

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3 years ago

Charles is walking arounda fountain that has a circumference of 124ft .what is the diameter of the fountain?

Dovator [93]

Hello.

To find the diameter you use this equation:
Radiascm x 2/pie

So it would be 124=π*d
d=124/π

So the answer would be :
d=39.47=39.4 feet

Have a nice day

6 0

3 years ago

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kodGreya [7K]

Answer: $2.10

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NARA [144]

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