(4.3 x 10^-3)(2 x 10^-2) in standard form

If two cylinders are similar and the ratio between the altitude lengths is 2:3, what is the ratio of their volumes

hram777 [196]

Given:

ratio of altitude height = 2/3

Required:

ratio of volume

Solution:

Assuming that the only difference that the cylinders has is the height, we can solve for the ratio of the volume.

The volume of a cylinder is equal to πr²×height.

ratio of volume = πr²×2/πr²×3

We cancel the pi and the r² since we assume that the cylinders have the same radius.By cancelling, we are left with:

ratio of volume = 2/3

8 0

2 years ago

Evaluate the expression. 5 - (4 - 2 - (6-6)) 8 2 5 3

Doss [256]

Answer: 3

Step-by-step explanation:

5−(4−2−(6−6))

=3

3 0

3 years ago

Read 2 more answers

Write out the form of the partial fraction decomposition of the function. Do not determine the numerical values of the coefficie

Dvinal [7]

For part (a), you have

$\dfrac x{x^2+x-6}=\dfrac x{(x+3)(x-2)}=\dfrac a{x+3}+\dfrac b{x-2}$
$x=a(x-2)+b(x+3)$

If $x=2$ , then $2=b(2-3)\implies b=-2$ .

If $x=-3$ , then $-3=a(-3-2)\implies a=\dfrac35$ .

So,

$\dfrac x{x^2+x-6}=\dfrac 3{5(x+3)}-\dfrac 2{x-2}$

For part (b), since the degrees of the numerator and denominator are the same, you first need to find the quotient and remainder upon division.

$\dfrac{x^2}{x^2+x+2}=\dfrac{x^2+x+2-x-2}{x^2+x+2}=1-\dfrac{x+2}{x^2+x+2}$

In the remainder term, the denominator $x^2+x+2$ can't be factorized into linear components with real coefficients, since the discriminant is negative $(1-4\times1\times2=-7)$ . However, you can still factorized over the complex numbers, so a partial fraction decomposition in terms of complexes does exist.

$x^2+x+2=0\implies x=-\dfrac12\pm\dfrac{\sqrt7}2i$
$\implies x^2+x+2=\left(x-\left(-\dfrac12+\dfrac{\sqrt7}2i\right)\right)\left(x-\left(-\dfrac12-\dfrac{\sqrt7}2i\right)\right)$
$\implies x^2+x+2=\left(x+\dfrac12-\dfrac{\sqrt7}2i\right)\left(x+\dfrac12+\dfrac{\sqrt7}2i\right)$

Then you have

$\dfrac{x+2}{x^2+x+2}=\dfrac a{x+\dfrac12-\dfrac{\sqrt7}2i}+\dfrac b{x+\dfrac12+\dfrac{\sqrt7}2i}$
$x+2=a\left(x+\dfrac12+\dfrac{\sqrt7}2i\right)+b\left(x+\dfrac12-\dfrac{\sqrt7}2i\right)$

When $x=-\dfrac12-\dfrac{\sqrt7}2i$ , you have

$-\dfrac12-\dfrac{\sqrt7}2i+2=b\left(-\dfrac12-\dfrac{\sqrt7}2i+\dfrac12-\dfrac{\sqrt7}2i\right)$
$\dfrac32-\dfrac{\sqrt7}2i=-\sqrt7ib$
$b=\dfrac12+\dfrac3{2\sqrt7}i=\dfrac1{14}(7+3\sqrt7i)$

When $x=-\dfrac12+\dfrac{\sqrt7}2i$ , you have

$-\dfrac12+\dfrac{\sqrt7}2i+2=a\left(-\dfrac12+\dfrac{\sqrt7}2i+\dfrac12+\dfrac{\sqrt7}2i\right)$
$\dfrac32+\dfrac{\sqrt7}2i=\sqrt7ia$
$a=\dfrac12-\dfrac3{2\sqrt7}i=\dfrac1{14}(7-3\sqrt7i)$

So, you could write

$\dfrac{x^2}{x^2+x+2}=1-\dfrac{x+2}{x^2+x+2}=1-\dfrac {7-3\sqrt7i}{14\left(x+\dfrac12-\dfrac{\sqrt7}2i\right)}-\dfrac {7+3\sqrt7i}{14\left(x+\dfrac12+\dfrac{\sqrt7}2i\right)}$

but that may or may not be considered acceptable by that webpage.

5 0

2 years ago

Read 2 more answers

6. slope = 9, (-5, 2) no links or bots please

Arada [10]

Answer: y= 9x -5

Step-by-step explanation:

3 0

2 years ago

Please help me with this geometry problem, I'd really appreciate it :)

Strike441 [17]

Hello from MrBillDoesMath!

Answer:

x = 31

Discussion:

angle A + angle C + angle B = 180 (180 degrees in a triangle)

angle A + 57 + 61 = 180 => (substitution)

angle A + 118 = 180 =>

angle A = 180 -118 = 62

By the congruence statement, angle A = angle D = 2x so

62 = 2x =>

x = 31

Thank you,

MrB

6 0

3 years ago