Question

May someone please help me with the problem below. I answered some questions but don't know if they're right

Answer 1

I think it is correct!

Answer 2

Thanks Im confused with the 1st questions the one that has the graph. I don't know how to find the equation

Answer 3

Looks good, except maybe phase shift. The answer "pi" is _technically_ correct, but a tough grader might expect "-pi" even though the two shifts are identical in the real world. (When I taught, we used A*sin(x - phi) as the baseline equation. So it also depends on the way you have been taught.)

Answer 4

oh okay thank you and do you know how to find the equation for the first one with the graph?

Answer 5

For previous question on the page, what is your question. Can you get the amplitude, but just aren't sure? Can you get the distance between peaks? Is it something else you are missing?

Answer 6

For the first one note that the graph passes though the origin and again at (pi,0) and as amplitude 2. Which trig ratio passes through the origin and has amplitude 1?

Answer 7

so would the equation be sin(x+2)

Answer 8

@wintersuntime , slow down to welshfella's pace. He's going to build up to the final answer (NOT sin(x+@) ! ) and he is quite good at it!

Answer 9

oh ok sorry

Answer 10

I'll be back in 5 minutes

Answer 11

ok

Answer 12

OK so it is a sine graph.
sin x is the basic graph that has an amplitude of 1 and passes through (0,00. The maximum and minimum values of sin x are 1 and -1).

But our graph has an amplitude of 2 so what difference does that make to the function?

Answer 13

Note: y = a sin x has amplitude a

Answer 14

I dont understand what difference it would make to the graph, wouldn't it just stretch the graph

Answer 15

yes - by a factor 2

Answer 16

so where does the 2 go?

Answer 17

a = 2

Answer 18

from the graph, we see that there are \(3 +1/2\) half waves inside a length of 11 units, so we can write this:
\[\left( {3 + \frac{1}{2}} \right)\;\frac{T}{2} = 11 \Rightarrow T = \frac{{44}}{7}\]
where \(T\) is the period of the wave

Answer 19

okay why 44 ?

Answer 20

since, we have this computation:
\[\left( {3 + \frac{1}{2}} \right)\;\frac{T}{2} = \frac{7}{4} \cdot T = 11\]

Answer 21

or:
\[\frac{7}{4} \cdot T = 11\]

Answer 22

oh okay

Answer 23

now, I multiply both sides by \(4/7\):
\[\frac{4}{7} \cdot \frac{7}{4} \cdot T = 11 \cdot \frac{4}{7}\]

Answer 24

after a simplification, I get:
\[T = \frac{{44}}{7}\]

Answer 25

and that would equal 6.28

Answer 26

no, since the period of the wave is \(not\) equal to \(2 \pi\)

Answer 27

oh okay

Answer 28

we have:
\(44/7=6.285...\) namely the wave repeat itself after a length of 6.285, as we can see from the picture

Answer 29

repeats*

Answer 30

so the equation of such wave, is:
\[y = A\sin \left( {\frac{{2\pi }}{T}x} \right)\]
where \(A=2\) and \(T=44/7\)

Answer 31

okay thank you

Answer 32

:)

Answer 33

wow u had a lot of help