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3 years ago

PLEASE HELPP URGENT 20 points!!!

Mathematics

1 answer:

MAVERICK [17]3 years ago

8 0

If you're talking about the second part of the question where it asks you which facts you included in your answer, you can choose any of them and it will be counted right.

You might be interested in

Which of the following represents a geometric series (remember what a series is as opposed to a sequence)?

juin [17]

Answer:

4 + 12 + 36 + ...

Step-by-step explanation:

4, 12, 36, ... is a geometric sequence, it has a common ratio of $r=\frac{36}{12}=\frac{12}{4}=3$

When we add the terms of a geometric sequence we get a geometric series.

4+12+36+ ... is a geometric series, it has a common ratio of $r=\frac{36}{12}=\frac{12}{4}=3$

4 + 12 + 20 + ... is not a geometric series because it has no common ratio

$\frac{20}{12}\ne \frac{12}{4}$

The second choice is correct

8 0

3 years ago

For what integer value of x is 3x+5>11 and x-3 <1?

Andre45 [30]

3x + 5 > 11
3x + (5 - 5) > 11 - 5
3x > 6
3x / 3 > 6 / 3
x > 2

x - 3 < 1
x (-3 + 3) < 1 + 3
x < 4

When subtracting / adding values to both sides, the inequality does not change.

When multiplying / dividing by a positive value, the inequality also doesn't change, but when multiplying , dividing with a negative value, the inequality must be flipped.

7 0

3 years ago

Use the Trapezoidal Rule, the Midpoint Rule, and Simpson's Rule to approximate the given integral with the specified value of n.

Vera_Pavlovna [14]

Split up the integration interval into 4 subintervals:

$\left[0,\dfrac\pi8\right],\left[\dfrac\pi8,\dfrac\pi4\right],\left[\dfrac\pi4,\dfrac{3\pi}8\right],\left[\dfrac{3\pi}8,\dfrac\pi2\right]$

The left and right endpoints of the $i$ -th subinterval, respectively, are

$\ell_i=\dfrac{i-1}4\left(\dfrac\pi2-0\right)=\dfrac{(i-1)\pi}8$

$r_i=\dfrac i4\left(\dfrac\pi2-0\right)=\dfrac{i\pi}8$

for $1\le i\le4$ , and the respective midpoints are

$m_i=\dfrac{\ell_i+r_i}2=\dfrac{(2i-1)\pi}8$

Trapezoidal rule

We approximate the (signed) area under the curve over each subinterval by

$T_i=\dfrac{f(\ell_i)+f(r_i)}2(\ell_i-r_i)$

so that

$\displaystyle\int_0^{\pi/2}\frac3{1+\cos x}\,\mathrm dx\approx\sum_{i=1}^4T_i\approx\boxed{3.038078}$

Midpoint rule

We approximate the area for each subinterval by

$M_i=f(m_i)(\ell_i-r_i)$

so that

$\displaystyle\int_0^{\pi/2}\frac3{1+\cos x}\,\mathrm dx\approx\sum_{i=1}^4M_i\approx\boxed{2.981137}$

Simpson's rule

We first interpolate the integrand over each subinterval by a quadratic polynomial $p_i(x)$ , where

$p_i(x)=f(\ell_i)\dfrac{(x-m_i)(x-r_i)}{(\ell_i-m_i)(\ell_i-r_i)}+f(m)\dfrac{(x-\ell_i)(x-r_i)}{(m_i-\ell_i)(m_i-r_i)}+f(r_i)\dfrac{(x-\ell_i)(x-m_i)}{(r_i-\ell_i)(r_i-m_i)}$

so that

$\displaystyle\int_0^{\pi/2}\frac3{1+\cos x}\,\mathrm dx\approx\sum_{i=1}^4\int_{\ell_i}^{r_i}p_i(x)\,\mathrm dx$

It so happens that the integral of $p_i(x)$ reduces nicely to the form you're probably more familiar with,

$S_i=\displaystyle\int_{\ell_i}^{r_i}p_i(x)\,\mathrm dx=\frac{r_i-\ell_i}6(f(\ell_i)+4f(m_i)+f(r_i))$

Then the integral is approximately

$\displaystyle\int_0^{\pi/2}\frac3{1+\cos x}\,\mathrm dx\approx\sum_{i=1}^4S_i\approx\boxed{3.000117}$

Compare these to the actual value of the integral, 3. I've included plots of the approximations below.

3 0

3 years ago

Find a number which decreased by 12 equals 3 times it’s opposite

-BARSIC- [3]

Answer:

The number is 3.

Step-by-step explanation:

To find : A number which decreased by 12 equals 3 times it’s opposite ?

Solution :

Let the number be 'x'.

It's opposite is '-x'.

A number which decreased by 12 equals 3 times it’s opposite

i.e. $x - 12 = 3(-x)$

Solving the equation,

$x-12=-3x$

$x+3x=12$

$4x=12$

$x=\frac{12}{4}$

$x=3$

Therefore, the number is 3.

4 0

3 years ago

Choose all of the following scenarios below that contain biased samples.

Korvikt [17]

Answer:

1 and 3 are biased

Step-by-step explanation:

A biased sample is ond where all individuals were not given equal likelihood of being selected.

Number 1;

Picking students from the cafeteria would lead to sampling bias because not every student from the school eats from the cafeteria. Those she selected can not be used to account for the whole school. Those that use the cafeteria are only a representation of the whole school and not the entire school.

For number 3:

Paul is interested in finding the mean number of cloth shoppers In a mall and is only collecting data from one clothing store without considering other stores in the mall.

7 0

2 years ago

Read 2 more answers