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3 years ago

15

A stone is thrown upward from ground level. With what minimum speed should the stone be thrown so as to reach a height of 36 fee

t?

1 answer:

jeyben [28]3 years ago

5 0

15mph ...................................................

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The two-way table shows the number of students in a school who like reading and/or gardening.

lisov135 [29]

hello i just took the test the answer is 26

5 0

3 years ago

Consider the differential equation y'' − y' − 20y = 0. Verify that the functions e−4x and e5x form a fundamental set of solution

KIM [24]

Answer:

Therefore $e^{-4x}$ and $e^{5x}$ are fundamental solution of the given differential equation.

Therefore $e^{-4x}$ and $e^{5x}$ are linearly independent, since $W(e^{-4x},e^{5x})=9e^x\neq 0$

The general solution of the differential equation is

$y=c_1e^{-4x}+c_2e^{5x}$

Step-by-step explanation:

Given differential equation is

y''-y'-20y =0

Here P(x)= -1, Q(x)= -20 and R(x)=0

Let trial solution be $y=e^{mx}$

Then, $y'=me^{mx}$ and $y''=m^2e^{mx}$

$\therefore m^2e^{mx}-m e^{mx}-20e^{mx}=0$

$\Rightarrow m^2-m-20=0$

$\Rightarrow m^2-5m+4m-20=0$

$\Rightarrow m(m-5)+4(m-5)=0$

$\Rightarrow (m-5)(m+4)=0$

$\Rightarrow m=-4,5$

Therefore the complementary function is = $c_1e^{-4x}+c_2e^{5x}$

Therefore $e^{-4x}$ and $e^{5x}$ are fundamental solution of the given differential equation.

If $y_1$ and $y_2$ are the fundamental solution of differential equation, then

$W(y_1,y_2)=\left|\begin{array}{cc}y_1&y_2\\y'_1&y'_2\end{array}\right|\neq 0$

Then $y_1$ and $y_2$ are linearly independent.

$W(e^{-4x},e^{5x})=\left|\begin{array}{cc}e^{-4x}&e^{5x}\\-4e^{-4x}&5e^{5x}\end{array}\right|$

$=e^{-4x}.5e^{5x}-e^{5x}.(-4e^{-4x})$

$=5e^x+4e^x$

$=9e^x\neq 0$

Therefore $e^{-4x}$ and $e^{5x}$ are linearly independent, since $W(e^{-4x},e^{5x})=9e^x\neq 0$

Let the the particular solution of the differential equation is

$y_p=v_1e^{-4x}+v_2e^{5x}$

$\therefore v_1=\int \frac{-y_2R(x)}{W(y_1,y_2)} dx$

and

$\therefore v_2=\int \frac{y_1R(x)}{W(y_1,y_2)} dx$

Here $y_1= e^{-4x}$ , $y_2=e^{5x}$ , $W(e^{-4x},e^{5x})=9e^x$ ,and $R(x)=0$

$\therefore v_1=\int \frac{-e^{5x}.0}{9e^x}dx$

=0

and

$\therefore v_2=\int \frac{e^{5x}.0}{9e^x}dx$

=0

The the P.I = 0

The general solution of the differential equation is

$y=c_1e^{-4x}+c_2e^{5x}$

7 0

3 years ago

What is an expression equivalent to 9(47) using the distributive property?

pickupchik [31]

The answer is 9(40+7)

7 0

3 years ago

Samual has a collection of toy cars his favorites are the 27 red ones which makes up 60% of his collection how many toy cars dos

vagabundo [1.1K]

Answer:

45

Step-by-step explanation:

Use khan acedaemy

5 0

2 years ago

Byron’s workout starts with a

Hatshy [7]

Answer:

An equation in point-slope form that represents Byron’s distance from home, y, after x hours is y=4x+2

Step-by-step explanation:

Speed of Byron = 4 miles / hour

Distance traveled in x hours = $Speed \times time$

Distance traveled in x hours = 4x

We are given that After half an hour of running, he is 2 miles from home

So, Total distance = 4x+2

So, y = 4x+2

Hence an equation in point-slope form that represents Byron’s distance from home, y, after x hours is y=4x+2

7 0

3 years ago