Can somebody help me with this

An equation and the first step in its solution are shown: Equation: x2 + 8x - 9 = 0

Novay_Z [31]

Answer- A-16

Because when doing completing the square, you divide the coefficient of x by 2, which is 4, and the square it which is 16

3 0

2 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

Ax+3=23 if a=0 plz help

VladimirAG [237]

Answer:

x = $\frac{23}{a}$

Step-by-step explanation:

Given equation is,

ax + 3 = 23

To solve this equation for the value of x isolate the variable 'x' on the one side of the equation.

Step 1,

Subtract 3 from both the sides of the equation.

ax + 3 - 3 = 23 - 3

ax = 20

Step 2,

Divide the equation by a,

$\frac{ax}{a}=\frac{23}{a}$

x = $\frac{23}{a}$

Therefore, x = $\frac{23}{a}$ will be the answer.

6 0

3 years ago

A jet files at an altitude of 52,800 feet. what is the height of the hey on miles

Triss [41]

There are 5,280 feet in a mile. so 52,800 feet is 10 miles.

4 0

3 years ago

Read 2 more answers

You are playing a board game with a friend. She owns and has developed the tiles Green Gardens and Silver Sidewalks. If you roll

IgorC [24]

Answer:

The expected value can be calculated as:

Es = x₁*p₁ + x₂*p2 + .....

where xₙ is the event (the amount of money that you win or lose, and pₙ is the probability for the event)

for example, in a 10 side dice, the probability of obtaining a specific number is 1/10.

we have a d10 i guess (a dice with 10 sides, 1 to 10)

if you roll from 1 to 7, nothing happens.

If you roll an 8, you lose $1500

if you roll a 9, you lose $75

if you roll a 10, you lose $2000 (and the game)

the expected value is,

Es = 1/10*(7*0 - 1*$1500 - 1*$75 - 1*$2000) = -$357

in the second case, you start paying $500.

if you roll a 7, you must pay $1000, if else, nothing happens.

Then the expected value is

Es = -$500 - 1/10*(-1*$1000 + 9*$0) = -$600

So the expected value is smaller in this case, so the deal is not fair

7 0

3 years ago