The complement of 10 percent is 90 percent or in decimal .90.

Homework help please I'll give you 10 points and brainliest

DaniilM [7]

Answer:

c)

Step-by-step explanation:

Use 49 instead of 14 for 7²

Reason: 7² = 7 * 7 = 49

Not 14 as 7*2 = 14

6 0

2 years ago

Y''+y'+y=0, y(0)=1, y'(0)=0

mars1129 [50]

Answer:

$y=e^{\frac{-t}{2}}\left ( \cos\left ( \frac{\sqrt{3}t}{2} \right )+\frac{1}{\sqrt{3}}\sin \left ( \frac{\sqrt{3}t}{2} \right ) \right )$

Step-by-step explanation:

A second order linear , homogeneous ordinary differential equation has form $ay''+by'+cy=0$ .

Given: $y''+y'+y=0$

Let $y=e^{rt}$ be it's solution.

We get,

$\left ( r^2+r+1 \right )e^{rt}=0$

Since $e^{rt}\neq 0$ , $r^2+r+1=0$

{ we know that for equation $ax^2+bx+c=0$ , roots are of form $x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$ }

We get,

$y=\frac{-1\pm \sqrt{1^2-4}}{2}=\frac{-1\pm \sqrt{3}i}{2}$

For two complex roots $r_1=\alpha +i\beta \,,\,r_2=\alpha -i\beta$ , the general solution is of form $y=e^{\alpha t}\left ( c_1\cos \beta t+c_2\sin \beta t \right )$

i.e $y=e^{\frac{-t}{2}}\left ( c_1\cos\left ( \frac{\sqrt{3}t}{2} \right )+c_2\sin \left ( \frac{\sqrt{3}t}{2} \right ) \right )$

Applying conditions y(0)=1 on $e^{\frac{-t}{2}}\left ( c_1\cos\left ( \frac{\sqrt{3}t}{2} \right )+c_2\sin \left ( \frac{\sqrt{3}t}{2} \right ) \right )$ , $c_1=1$

So, equation becomes $y=e^{\frac{-t}{2}}\left ( \cos\left ( \frac{\sqrt{3}t}{2} \right )+c_2\sin \left ( \frac{\sqrt{3}t}{2} \right ) \right )$

On differentiating with respect to t, we get

$y'=\frac{-1}{2}e^{\frac{-t}{2}}\left ( \cos\left ( \frac{\sqrt{3}t}{2} \right )+c_2\sin \left ( \frac{\sqrt{3}t}{2} \right ) \right )+e^{\frac{-t}{2}}\left ( \frac{-\sqrt{3}}{2} \sin \left ( \frac{\sqrt{3}t}{2} \right )+c_2\frac{\sqrt{3}}{2}\cos\left ( \frac{\sqrt{3}t}{2} \right )\right )$

Applying condition: y'(0)=0, we get $0=\frac{-1}{2}+\frac{\sqrt{3}}{2}c_2\Rightarrow c_2=\frac{1}{\sqrt{3}}$

Therefore,

$y=e^{\frac{-t}{2}}\left ( \cos\left ( \frac{\sqrt{3}t}{2} \right )+\frac{1}{\sqrt{3}}\sin \left ( \frac{\sqrt{3}t}{2} \right ) \right )$

3 0

2 years ago

a container built in the shape of a cylinder has a circular base with a radius of 1.5 meters. the altitude of the container is 3

HACTEHA [7]

Answer:

im assuming you need the volume of this container:

$Volume=\pi r^{2} h$

$Volume=\pi (1.5^{2} )(3.5)=24.7$

8 0

3 years ago

Read 2 more answers

Write and solve a system of equations to determine how many tickets were sold before and at the music festival. PLEASE HELPPP

strojnjashka [21]

b = number of tickets sold before

a = number of tickets sold after

cost of a ticket = number of tickets times cost per ticket

before cost = 39.95b

after cost = 54.95a

total cost = 925000

39.95b + 54.95a = 925000

total number tickets = 20000

b + a = 20000

we have

39.95b + 54.95a = 925000

b + a = 20000

multiply second equation by -39.95 and add to first equation

39.95b + 54.95a = 925000

-39.95b-39.95a = -799000 +

0b+15a = 126000

15a = 126000

divide bot sides by 15

a = 8400

sub back

b + a = 20000

b+8400 = 20000

minus 8400 both sides

b = 11600

11,600 tickets sold before

8400 tickets sold after

3 0

2 years ago

A rectangle has a length of 4 cm, a width

Blizzard [7]

19 is the answer to this question

4 0

3 years ago