All categories

3 years ago

Evaluate 3r³+5,when r=2

Mathematics

2 answers:

Elza [17]3 years ago

8 0

Answer:

Step-by-step explanation:

Alexxx [7]3 years ago

7 0

Answer:

221

Step-by-step explanation:

r=2

32³+5=

3x2= 6

6³ +5

6x6x6 = 216

216 + 5 =221

Hope this helps please give me brainliest!

You might be interested in

18 is 25% of what number? A) 36

Nezavi [6.7K]

Answer:

c) 72

Step-by-step explanation:

multiply 18 by 4

5 0

3 years ago

Read 2 more answers

Tracy needs to find the length and width of the equipment storage room where she works. The room is 2 meters longer than it is w

____ [38]

Answer:

3 meters

Step-by-step explanation:

We assume the storage room is a rectangle, like most rooms, no indication it is otherwise.

We know it's a rectangle and not a square because it is longer than wide.

We have the perimeter measurement (16 meters).

So, we can make the following equation:

2x + 2y = 16

x being the width of the room, y being it's length. A perimeter is the sum of all sides.

We also know the room is 2 meters longer than wide... so:

y = x + 2

If we replace y in the first equation by its value relative to x, we get:

2x + 2(x + 2) = 16 which becomes

2x + 2x + 4 = 16

4x =12

thus x = 3

Width: 3 meters

Length: 5 meters.

Confirms the 16 meters perimeter.

5 0

3 years ago

Read 2 more answers

Derivative of tan(2x+3) using first principle

kodGreya [7K]

$f(x)=\tan(2x+3)$

The derivative is given by the limit

$f'(x)=\displaystyle\lim_{h\to0}\frac{f(x+h)-f(x)}h$

You have

$\displaystyle\lim_{h\to0}\frac{\tan(2(x+h)+3)-\tan(2x+3)}h$
$\displaystyle\lim_{h\to0}\frac{\tan((2x+3)+2h)-\tan(2x+3)}h$

Use the angle sum identity for tangent. I don't remember it off the top of my head, but I do remember the ones for (co)sine.

$\tan(a+b)=\dfrac{\sin(a+b)}{\cos(a+b)}=\dfrac{\sin a\cos b+\cos a\sin b}{\cos a\cos b-\sin a\sin b}=\dfrac{\tan a+\tan b}{1-\tan a\tan b}$

By this identity, you have

$\tan((2x+3)+2h)=\dfrac{\tan(2x+3)+\tan2h}{1-\tan(2x+3)\tan2h}$

So in the limit you get

$\displaystyle\lim_{h\to0}\frac{\dfrac{\tan(2x+3)+\tan2h}{1-\tan(2x+3)\tan2h}-\tan(2x+3)}h$
$\displaystyle\lim_{h\to0}\frac{\tan(2x+3)+\tan2h-\tan(2x+3)(1-\tan(2x+3)\tan2h)}{h(1-\tan(2x+3)\tan2h)}$
$\displaystyle\lim_{h\to0}\frac{\tan2h+\tan^2(2x+3)\tan2h}{h(1-\tan(2x+3)\tan2h)}$
$\displaystyle\lim_{h\to0}\frac{\tan2h}h\times\lim_{h\to0}\frac{1+\tan^2(2x+3)}{1-\tan(2x+3)\tan2h}$
$\displaystyle\frac12\lim_{h\to0}\frac1{\cos2h}\times\lim_{h\to0}\frac{\sin2h}{2h}\times\lim_{h\to0}\frac{\sec^2(2x+3)}{1-\tan(2x+3)\tan2h}$

The first two limits are both 1, and the single term in the last limit approaches 0 as $h\to0$ , so you're left with

$f'(x)=\dfrac12\sec^2(2x+3)$

which agrees with the result you get from applying the chain rule.

7 0

3 years ago

Solve each proportion, round to one decimal place.<br> 4/9=x/20

guapka [62]

In order to solve a proportion you need to cross multiply, so you would do:

4x20 and 9xX and you would get...

9x=80

then divide by nine to get

x=8.8888888889

which is technically 8.9

3 0

3 years ago

There is 1/ 3 gallon of water in a 3-gallon container. What fraction of the container is filled?

kolbaska11 [484]

Step-by-step explanation:

2/3 gallons is empty

1/3 gallons is filled

3*1/3= 1

1 gallon filled

6 0

3 years ago

Read 2 more answers