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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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Please help me...............

Contact [7]

Answer:

150

Step-by-step explanation:

because acute angle is less than 90 degree

6 0

2 years ago

If the sum of the zereos of the quadratic polynomial is 3x^2-(3k-2)x-(k-6) is equal to the product of the zereos, then find k?

lys-0071 [83]

Answer:

Step-by-step explanation:

So I'm going to use vieta's formula.

Let u and v the zeros of the given quadratic in ax^2+bx+c form.

By vieta's formula:

1) u+v=-b/a

2) uv=c/a

We are also given not by the formula but by this problem:

3) u+v=uv

If we plug 1) and 2) into 3) we get:

-b/a=c/a

Multiply both sides by a:

-b=c

Here we have:

a=3

b=-(3k-2)

c=-(k-6)

So we are solving

-b=c for k:

3k-2=-(k-6)

Distribute:

3k-2=-k+6

Add k on both sides:

4k-2=6

Add 2 on both side:

4k=8

Divide both sides by 4:

k=2

Let's check:

$3x^2-(3k-2)x-(k-6) \text{ with }k=2$ :

$3x^2-(3\cdot 2-2)x-(2-6)$

$3x^2-4x+4$

I'm going to solve $3x^2-4x+4=0$ for x using the quadratic formula:

$\frac{-b\pm \sqrt{b^2-4ac}}{2a}$

$\frac{4\pm \sqrt{(-4)^2-4(3)(4)}}{2(3)}$

$\frac{4\pm \sqrt{16-16(3)}}{6}$

$\frac{4\pm \sqrt{16}\sqrt{1-(3)}}{6}$

$\frac{4\pm 4\sqrt{-2}}{6}$

$\frac{2\pm 2\sqrt{-2}}{3}$

$\frac{2\pm 2i\sqrt{2}}{3}$

Let's see if uv=u+v holds.

$uv=\frac{2+2i\sqrt{2}}{3} \cdot \frac{2-2i\sqrt{2}}{3}$

Keep in mind you are multiplying conjugates:

$uv=\frac{1}{9}(4-4i^2(2))$

$uv=\frac{1}{9}(4+4(2))$

$uv=\frac{12}{9}=\frac{4}{3}$

Let's see what u+v is now:

$u+v=\frac{2+2i\sqrt{2}}{3}+\frac{2-2i\sqrt{2}}{3}$

$u+v=\frac{2}{3}+\frac{2}{3}=\frac{4}{3}$

We have confirmed uv=u+v for k=2.

4 0

2 years ago

1. The US Mint has a specification that pennies have a mean weight of 2.5g. From a sample of 37 pennies, the mean weight is foun

Evgesh-ka [11]

Answer:

the pennies does not conform to the US mints specification

Step-by-step explanation:

z = (variate -mean)/ standard deviation

z= 2.5 - 2.4991 / 0.01648 = 0.0546

we are going to check the value of z in the normal distribution table, which is the table bounded by z.

checking for z= 0.0 under 55 gives 0.0219 (value gotten from the table of normal distribution)

we subtract the value of z from 0.5 (1- (0.5+0.0219)) = 0.4781 > 0.05claim

since 0.4781 > 0.05claim, therefore, the pennies does not conform to the US mints specification

the claim state a 5% significance level whereas the calculated significance level is 47.81%. therefore, the claim should be rejected

7 0

3 years ago

Suppose a, b, and c are all negative numbers. How do you find the distance between the points (a,b) and (a,c)?

Alex787 [66]

Answer:

Step-by-step explanation:

Let's say if b = -2 and c = -3

-2-(-3) = 1 that would be the distance between them. If it was D then you would need absolute value.

Hope this helps! Have a nice day!

4 0

2 years ago

How do you simplify this problem

vampirchik [111]

Reduce the fraction with 2
$\frac{2 \times x {}^{ - 2} y {}^{3}z {}^{ - 1} }{xy} \\ \\ \frac{3y {}^{2}z {}^{ - 1} }{x {}^{3} } \\ \\ \frac{3y {}^{2} }{x {}^{3} z}$

7 0

3 years ago