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3 years ago

Robin can clean 72 rooms in 666 days.

Mathematics

2 answers:

Leokris [45]3 years ago

7 0

Answer:

108 rooms

Step-by-step explanation:

Robin can clean 72 rooms in 666 days

means in 666 days rooms that can be clean is 72 rooms

in 1 days rooms that can be clean is 72/666 rooms

in 999 days rooms can be clean is 999\times 72\div 666

after solving we get 108 answer

kati45 [8]3 years ago

7 0

Answer:

108 rooms love

Step-by-step explanation:

btw its depree

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Use Newton's Method to approximate the zero(s) of the function. Continue the iterations until two successive approximations diff

liubo4ka [24]

Answer:

There is only one real zero and it is located at x = 1.359

Step-by-step explanation:

After the 4th iteration the solution was repeating the first 3 decimal places. The formula for Newton's Method is

$x_{n}-\frac{f(x_{n}) }{f'(x_{n}) }$

If our function is

$f(x)=x^5+x-6$

then the first derivative is

$f'(x)=5x^4+1$

I graphed this on my calculator to see where the zero(s) looked like they might be, and saw there was only one real one, somewhere between 1 and 2. I started with my first guess being x = 1.

When I plugged in a 1 for x, I got a zero of 5/3.

Plugging in 5/3 and completing the process again gave me 997/687

Plugging in 997/687 and completing the process again gave me 1.36976

Plugging in 1.36976 and completing the process again gave me 1.359454

Plugging in 1.359454 and completing the process again gave me 1.359304

Since we are looking for accuracy to 3 decimal places, there was no need to go further.

Checking the zeros on the calculator graphing program gave me a zero of 1.3593041 which is exactly the same as my 5th iteration!

Newton's Method is absolutely amazing!!!

5 0

4 years ago

Set A of six numbers has a standard deviation of 3 and set B of four numbers has a standard deviation of 5. Both sets of numbers

Alenkinab [10]

Given:

$\sigma_A=3$

$n_A=6$

$\sigma_B=5$

$n_B=4$

$\overline{x}_A=\overline{x}_B$

To find:

The variance. of combined set.

Solution:

Formula for variance is

$\sigma^2=\dfrac{\sum (x_i-\overline{x})^2}{n}$ ...(i)

Using (i), we get

$\sigma_A^2=\dfrac{\sum (x_i-\overline{x}_A)^2}{n_A}$

$(3)^2=\dfrac{\sum (x_i-\overline{x}_A)^2}{6}$

$9=\dfrac{\sum (x_i-\overline{x}_A)^2}{6}$

$54=\sum (x_i-\overline{x}_A)^2$

Similarly,

$\sigma_B^2=\dfrac{\sum (x_i-\overline{x}_B)^2}{n_B}$

$(5)^2=\dfrac{\sum (x_i-\overline{x}_B)^2}{4}$

$25=\dfrac{\sum (x_i-\overline{x}_B)^2}{4}$

$100=\sum (x_i-\overline{x}_B)^2$

Now, after combining both sets, we get

$\sigma^2=\dfrac{\sum (x_i-\overline{x}_A)^2+\sum (x_i-\overline{x}_B)^2}{n_A+n_B}$

$\sigma^2=\dfrac{54+100}{6+4}$

$\sigma^2=\dfrac{154}{10}$

$\sigma^2=15.4$

Therefore, the variance of combined set is 15.4.

7 0

3 years ago

What is the correct factorisation of?<br>X^2+6x+8

MaRussiya [10]

Answer:

Step-by-step explanation:

Given that: x

+6x+8

+4x+2x+8, (split middle term)

=(x

+4x)+(2x+8), (group pair of terms)

=x(x+4)+2(x+4), (factor each binomials)

=(x+4)(x+2), (factor out common factor (x+4)

Hence factors of x

+6x+8 are (x+4)(x+2)

4 0

3 years ago

Read 2 more answers

Answer the question below fast

Cloud [144]

Answer:

The answer is 10.5 in decimal form

8 0

3 years ago

Derive the equation of the parabola with a focus of (-5,-5) and a directrix of y=7.

adoni [48]

Answer:

$y=-\frac{1}{24}(x+5)^2+1$

Step-by-step explanation:

The given parabola has its focus at (-5,-5) and the directrix is at: y=7.

The equation of such parabola is given by the formula:

$(x-h)^2=-4p(y-k)$

The vertex of the parabola is the midpoint of (-5,-5) and (-5,7).

$(\frac{-5+-5}{2},\frac{-5+7}{2} )=(-5,1)$

The value of p is the distance from the (-5,-5) to (-5,1).

p=|1--5|=6

We substitute the values of the vertex and p into the equation to get;

$(x--5)^2=-4(6)(y-1)$

$(x+5)^2=-24(y-1)$

$y=-\frac{1}{24}(x+5)^2+1$

3 0

3 years ago