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3 years ago

9

(60 points)--------------------

2 answers:

iren [92.7K]3 years ago

8 0

Answer:

be more clear pls- is it multiple choice orrr? that's all I need to know to answer it.

Step-by-step explanation:

scoray [572]3 years ago

6 0

Answer:

2 and 3 dear friend

Step-by-step explanation:

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Find the surface are of the figure below.

const2013 [10]

Answer:

Surface area≈ 179.38 m

Step-by-step explanation:

Right rectangular pyramid: length×width×height

= 8 m× 8 m× 6 m

≈179.38 m

6 0

3 years ago

Help me please! These are due today.

IrinaVladis [17]

Answer:

${x}^{2} + 3x$

Step-by-step explanation:

1.

Area of shaded region = Area of external rectangle - Area of internal rectangle

$= 4x(x + 2) - x(3x + 5) \\ = 4 {x}^{2} + 8x - 3 {x}^{2} - 5x \\ = 4 {x}^{2} - 3 {x}^{2} + 8x - 5x \\ = {x}^{2} + 3x \\$

2.

Let the width of the rectangle be x inches.

Therefore, length of the rectangle = (x + 3) inches

A.

Area of rectangle

$=(x + 3)\times x\\=x^2 + 3x\\$

B.

Width of rectangle = 4 inches

Length of rectangle = 4 + 3 = 7 inches

Area of rectangle = 7*4 = 28 square inches.

6 0

3 years ago

Problems 2.21, 2.22, 2.23

RoseWind [281]

Statements can be proved by contrapositive, contradiction or by induction.

<em>2.21 and 2.23 are proved by contrapositive</em>
<em>2.22 is proved by induction</em>

<u />

<u />

<u>2.21: If </u> $n^3$ <u> is even, then n is even (By contrapositive)</u>

The contrapositive of the above statement is that:

<em>If n is odd, then </em> $n^3$ <em> is odd</em>

Represent the value of n as:

$n = 2k + 1$ , where $k \ge 0$

Take the cube of both sides

$n^3 = (2k + 1)^3$

Expand

$n^3 = 8k^3 + 6k^2 + 6k + 1$

Group

$n^3 =[ 8k^3 + 6k^2 + 6k] + 1$

Factor out 2

$n^3 =2[4k^3 + 3k^2 + 3k] + 1$

Assume w is an integer; where:

$w =4k^3 + 3k^2 + 3k$

So, we have:

$n^3 =2w + 1$

The constant term (i.e. 1) means that $n^3$ is odd.

Hence, the statement has been proved by contrapositive.

<em>i.e. If n is odd, then </em> $n^3$ <em> is odd</em>

<u />

<u>2.22 </u> $3n + 4$ <u> is even, if and only if n is even</u>

We have: $3n + 4$ <u />

<u />

Assume that: $n = 2k + 2$ for $k \ge 0$

So, we have:

$3n + 4 = 3(2k + 2) + 4$

Open bracket

$3n + 4 = 6k + 6 + 4$

$3n + 4 = 6k + 10$

Factorize

$3n + 4 = 2(3k + 5)$

The factor of 2 means that $3n + 4$ is even.

<em>Hence, </em> $3n + 4$ <em> is even, if and only if n is even </em>

<em />

<u />

<u>2.22: </u> $s \ne -1$ <u> and </u> $t \ne -1$ <u>, then </u> $s + t + st \ne -1$ <u />

To do this, we prove by contrapositive.

The contrapositive of the above statement is:

If $s = -1$ and $t=-1$ , then $s + t + st = -1$

We have:

$s + t + st = -1$

Substitute the values of s and t in: $s + t + st = -1$

$-1 -1 -1 \times -1 = -1$

$-1 -1 + 1 = -1$

$-1 = -1$

Hence, by contrapositive:

If $s = -1$ and $t=-1$ , then $s + t + st = -1$

Read more about proofs at:

brainly.com/question/19643658

7 0

3 years ago

What inequality is shown in this graph?

Minchanka [31]

The solution of a linear inequality is the ordered pair that is a solution to all inequalities in the system and the graph of the linear inequality is the graph of all solutions of the system. Graph one line at the time in the same coordinate plane and shade the half-plane that satisfies the inequality

6 0

3 years ago

How do you find the derivative of y=3x+1−−−−−−√y =sqrt(3x+1)?

alina1380 [7]

$y=\sqrt{3x+1}\\
y'=\frac{1}{2\sqrt{3x+1}}\cdot3\\
y'=\frac{3}{2\sqrt{3x+1}}$

6 0

3 years ago