Which equation does the graph of the systems of equations solve?

Write the number in standard notation. 4.16 *10^-5 0.00000416 0.0000416 0.000416 –208

zalisa [80]

$4.16\cdot10^{-5}\\\\move\ the\ decimal\ 5\ place\ left\\\\4.16\cdot10^{-5}=0.0000416$

4 0

3 years ago

Find the probability of getting a king then an eight. Assume the cards are not replaced?

Nastasia [14]

There are 4 king and 4 eight cards inside 52 one deck of cards. The case asks for a king card and then an eight card.
To draw the king card, you have 4/52 probability.
To draw the eight card, you have 4/51 probability ( since the king card not replaced).

The total probability would be: 4*4/ 52*51= 4/663

4 0

2 years ago

Write an equation in point-slope form for each line (If possible please show work)

Archy [21]

Answer: y-2=1/4(x-1)

Step-by-step explanation:

The formula for point-slope is y-y₁=m(x-x₁). Since we are given the slope m, we can fill that in. We are also given the point (x₁,y₁). We can also fill that in.

y-2=1/4(x-1)

8 0

3 years ago

What are the coordinates of the first alien who needs to be rescued

Maslowich

huh? this does not make sense

7 0

3 years ago

Read 2 more answers

Solve using Fourier series.

Olin [163]

With $2L=\pi$ , the Fourier series expansion of $f(x)$ is

$\displaystyle f(x)\sim\frac{a_0}2+\sum_{n\ge1}a_n\cos\dfrac{n\pi x}L+\sum_{n\ge1}b_n\sin\dfrac{n\pi x}L$
$\displaystyle f(x)\sim\frac{a_0}2+\sum_{n\ge1}a_n\cos2nx+\sum_{n\ge1}b_n\sin2nx$

where the coefficients are obtained by computing

$\displaystyle a_0=\frac1L\int_0^{2L}f(x)\,\mathrm dx$
$\displaystyle a_0=\frac2\pi\int_0^\pi f(x)\,\mathrm dx$

$\displaystyle a_n=\frac1L\int_0^{2L}f(x)\cos\dfrac{n\pi x}L\,\mathrm dx$
$\displaystyle a_n=\frac2\pi\int_0^\pi f(x)\cos2nx\,\mathrm dx$

$\displaystyle b_n=\frac1L\int_0^{2L}f(x)\sin\dfrac{n\pi x}L\,\mathrm dx$
$\displaystyle b_n=\frac2\pi\int_0^\pi f(x)\sin2nx\,\mathrm dx$

You should end up with

$a_0=0$
$a_n=0$
(both due to the fact that $f(x)$ is odd)
$b_n=\dfrac1{3n}\left(2-\cos\dfrac{2n\pi}3-\cos\dfrac{4n\pi}3\right)$

Now the problem is that this expansion does not match the given one. As a matter of fact, since $f(x)$ is odd, there is no cosine series. So I'm starting to think this question is missing some initial details.

One possibility is that you're actually supposed to use the even extension of $f(x)$ , which is to say we're actually considering the function

$\varphi(x)=\begin{cases}\frac\pi3&\text{for }|x|\le\frac\pi3\\0&\text{for }\frac\pi3$

and enforcing a period of $2L=2\pi$ . Now, you should find that

$\varphi(x)\sim\dfrac2{\sqrt3}\left(\cos x-\dfrac{\cos5x}5+\dfrac{\cos7x}7-\dfrac{\cos11x}{11}+\cdots\right)$

The value of the sum can then be verified by choosing $x=0$ , which gives

$\varphi(0)=\dfrac\pi3=\dfrac2{\sqrt3}\left(1-\dfrac15+\dfrac17-\dfrac1{11}+\cdots\right)$
$\implies\dfrac\pi{2\sqrt3}=1-\dfrac15+\dfrac17-\dfrac1{11}+\cdots$

as required.

5 0

3 years ago