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3 years ago

Hello, how can I do this exercise the help is appreciated

Mathematics

1 answer:

Semenov [28]3 years ago

7 0

Answer:

5, 8, 11, 14, 17,....

f(n) = 5+3n where n is the number of steps after the first two. 7 steps is 20 faces.

Step-by-step explanation:

A sequence is a list of numbers that are related. The first number in the sequence is 5 since the first part of the stairs has 5 faces (5 squares, the dark don't count). Every time you add a "stair" you add 2 blocks - one underneath to support and one as the step. This adds 3 faces. So 5 becomes 8. Repeat and 8 becomes 11. You add 3 faces each time. So the sequence is

5, 8, 11, 14, 17,....

This is a constant pattern of adding 3 each time after the initial start. So we can write a rule. We start with 5 + 3(each stair step). So if the cube is 7 stairs high, that is 5 more repetitions of adding blocks after the start (remember the start has 2 steps already). So 5 + 3(5) = 20. 7 steps high will have 20 faces.

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If sin a= 12/13 and tan B 8/15 and angles a and b are in qundrant 1 find the value of tan (a+b)

natali 33 [55]

Answer:

The value of Tan (a + b) is $\frac{-220}{21}$ .

Step-by-step explanation:

Given as :

Tan b = $\frac{8}{15}$

Sin a = $\frac{12}{13}$

∵Sin Ф = $\dfrac{\textrm perpendicular}{\textrm Hypotenuse}$

So, $\dfrac{\textrm perpendicular}{\textrm Hypotenuse}$ = $\frac{12}{13}$

Now, Base² = Hypotenuse² - Perpendicular²

Or, Base² = 13² - 12²

Or, Base² = 169 - 144

Or, Base² = 25

∴ Base = $\sqrt{25}$ = 5

And Tan Ф = $\dfrac{\textrm perpendicular}{\textrm Base}$

Or, Tan a = $\frac{12}{5}$

Now, Tan (a + b) = $\dfrac{Tan a + Tan b}{1- Tan a Tanb}$

Or, Tan (a + b) = $\frac{\frac{12}{5}+\frac{8}{5}}{1-(\frac{12}{5}\times \frac{8}{15})}$

or, Tan (a + b) = $\frac{\frac{36+8}{15}}{\frac{75-96}{75}}$

or, Tan (a + b) = $\frac{\frac{44}{15}}{\frac{-21}{75}}$

Or, Tan (a + b) = $\frac{-220}{21}$

Hence The value of Tan (a + b) is $\frac{-220}{21}$ . Answer

5 0

3 years ago

A bag contains 3 red apples and 6 yellow apples. 3 apples are selected at random. Find the probability of selecting 1 red apple

Mrac [35]

Step-by-step explanation:

$number \: of \: ways \: to \: select \: 3 \: out \: of \: 9 = {C}^{9}_3 = 84$

$ways \: to \: select \: 1red \: and \: 2yellow \: apples \: = {C}^{3}_1 \times {C}^{6}_2 = 3 \times 15 = 45$

<u>Probability of selecting 1 red and 2 yellow apples</u> = 45 / 84 = 0.53

7 0

3 years ago

Divide -2 1/9 ÷ 7 3/5. Explain each step you used to find the quotient

Fudgin [204]

Answer:I am not sure.

Step-by-step explanation:

7 0

3 years ago

Estimate the area under the graph of f(x)=1/x+4 over the interval [-1,2] using four approximating rectangles and right endpoints

kiruha [24]

Answer:

Rn ≈ 0.6345

Ln ≈ 0.7595

Step-by-step explanation:

The interval from -1 to 2 has a width of (2 -(-1)) = 3. Dividing that into 4 equal intervals means each of those smaller intervals has width 3/4.

It can be useful to use a spreadsheet or graphing calculator to evaluate the function at all of the points that define these intervals:

x = -1, -.25, 0.50, 1.25, 2

Of course, the spreadsheet can easily compute the sum of products for you.

The approximation using right end-points will be the sum of products of the interval width (3/4) and the function value at the right end-points:

Rn = (3/4)f(-0.25) +(3/4)f(0.50) +(3/4)f(1.25) +(3/4)f(2)

Rn ≈ 0.6345

The approximation using left end-points will be the sum of products of the interval width (3/4) and the function value at the left end-points:

Ln = (3/4)f(-1) +(3/4)f(-0.25) +(3/4)f(0.50) +(3/4)f(1.25)

Ln ≈ 0.7595

_____

It is usually convenient to factor out the interval width, so only one multiplication needs to be done: (interval width)(sum of function values).

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4 years ago

A pelican starts at 60 feet above sea level. It descends 60 feet to catch a fish

Ksivusya [100]

Zero because 60 plus negative 60 equals 0

4 0

4 years ago