All categories

2 years ago

X=a-2by(2) make y the subject

Mathematics

1 answer:

sladkih [1.3K]2 years ago

3 0

Answer:

y = √{(a - x)/2b}

Step-by-step explanation:

x=a-2by²

2by² = a - x

divide through by 2b

y² = (a - x)/2b

y = √{(a - x)/2b}

You might be interested in

Each month, a retail store awards a blue ribbon to its employee of the month. The probability that Chloe is the employee of the

Alexxx [7]

P(E)= 29/100 * 49/100 = 0.1421= 14.21%

7 0

2 years ago

Read 2 more answers

A random sample from a normal population is obtained, and the data are given below. Find a 90% confidence interval for . 114 157

melamori03 [73]

Answer:

$103.160 \leq \sigma \leq 187.476$

And the upper bound rounded to the nearest integer would be 187.

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population mean or variance lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

The Chi Square distribution is the distribution of the sum of squared standard normal deviates .

$\bar X$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s represent the sample standard deviation

n represent the sample size

Solution to the problem

Data given: 114 157 203 257 284 299 305 344 378 410 421 450 478 480 512 533 545

The confidence interval for the population variance $\sigma^2$ is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma \leq \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

On this case we need to find the sample standard deviation with the following formula:

$s=sqrt{\frac{\sum_{i=1}^{17} (x_i -\bar x)^2}{n-1}}$

And in order to find the sample mean we just need to use this formula:

$\bar x =\frac{\sum_{i=1}^n x_i}{n}$

The sample mean obtained on this case is $\bar x= 362.941$ and the deviation s=132.250

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=17-1=16$

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a tabel to find the critical values.

The excel commands would be: "=CHISQ.INV(0.05,16)" "=CHISQ.INV(0.95,16)". so for this case the critical values are:

$\chi^2_{\alpha/2}=26.296$

$\chi^2_{1- \alpha/2}=7.962$

And replacing into the formula for the interval we got:

$\frac{(16)(132.250)^2}{26.296} \leq \sigma \leq \frac{(16)(132.250)^2}{7.962}$

$10641.959 \leq \sigma^2 \leq 35147.074$

Now we just take square root on both sides of the interval and we got:

$103.160 \leq \sigma \leq 187.476$

And the upper bound rounded to the nearest integer would be 187.

4 0

2 years ago

What are the solutions of the equation (2x + 3)2 + 8(2x + 3) + 11 = 0? Use u substitution and the quadratic formula to solve.

zvonat [6]

Answer:

$x=-2.38$

$x=-4.62$

Step-by-step explanation:

The question is $(2x+3)^2+8(2x+3)+11=0$

We let $u=2x+3$ , so the equation becomes:

$u^2+8u+11=0$

Where $a=1, b=8, c=11$

Putting it in the quadratic formula, we have:

Quadratic formula: $\frac{-b+-\sqrt{b^2-4ac} }{2a}$

Substituting we have: $\frac{-8+-\sqrt{(8)^2-4(1)(11)} }{2(1)}\\=\frac{-8+-\sqrt{20} }{2}\\=\frac{-8+-2\sqrt{5} }{2}\\=-4+\sqrt{5}, -4-\sqrt{5} }$

We let $u=2x+3$ , so x is:

$u=2x+3\\(-4+\sqrt{5})=2x+3\\x=\frac{-7+\sqrt{5}}{2}=-2.38$

and

$u=2x+3\\(-4-\sqrt{5})=2x+3\\x=\frac{-7-\sqrt{5}}{2}=-4.62$

The solutions of the equation is $x=-2.38$ (rounded to 2 decimal places), and $x=-4.62$ (rounded to 2 decimal places)

6 0

2 years ago

Jesse and Mark are jogging along the route shown at a rate of 12 miles per hour. They start by jogging south along Capitol Stree

Ilya [14]

The hypotenuse of the way that they have taken is equal to 2 miles. Jogging this distance with a rate of 5 miles per hour will take Jesse 0.4 hours. Further, for Mark to be back to the starting point, the total distance covered is 2.75. Dividing the distance by 12 miles per hour, it will take Mark only 0.23 hours. Thus, Mark will reach the initial point first.

4 0

2 years ago

Read 2 more answers

How is quadrilateral ABCD related to quadrilateral A'B'C'D' shown below?

coldgirl [10]

What you put is correct. A’B’C’D’ is what would be shown if you rotate ABCD 90 degrees clockwise

4 0

2 years ago