Question

@callisto

Answer 1

The other place is too messy

Answer 2

Part b?!

Answer 3

Yeah of the question. We solved only part a. He had to leave

Answer 4

For graph 1 of part b, No matter what I put for the value of b, why does it always cross at 0 in the y axis?

Answer 5

I think it would be easier to start with the second graph. it looks like a sine function.

Answer 6

Does this kind of make sense? y = 4sin(x+360)

Answer 7

you mean for the first graph?

Answer 8

Yes

Answer 9

sin(x+360) = sinx ....

Answer 10

Because when I graph that, It is very identical

Answer 11

OK, If its not, Lets do graph 2 first:)

Answer 12

Please give me few minutes or so. Let me graph it first :)

Answer 13

wow. y = 4sin(x+ pi/2) gives me the exact same graph

Answer 14

Actually... if you just take a look of the shape... That wouldn't help much..

Answer 15

Oh.

Answer 16

Some problems with that graph , sorry

Answer 17

Oh ok:)

Answer 18

That is it!
\[y=4\sin \left(\frac{\pi }{2}-\frac{1}{4}x\right)\]

Answer 19

It is?

Answer 20

This is for graph 1 right?

Answer 21

the first graph...

Answer 22

How did you determine the values of a and b?

Answer 23

Suddenly, I remember that cos(x) = sin(90- x)..
As you've got the result from (a), amplitude would be unchanged
So, the change cos to sin -> y= 4 (90 - (1/4 x ) ) => y=4(90 - 1/4 x )
the pi/2 is 90 degree in radian

Answer 24

Does this answer also work? y=−4sin1/4(x−360)

Answer 25

That is the same, just multiply the numbers and take out -1 as a factor, giving you the same solution

Answer 26

Mertsj, told me that we shouldnt use pi because the graph is in degrees

Answer 27

If that is true, I have to change all my answer:(

Answer 28

Hmm... I told you in the last solution... y=4(90 - 1/4 x )... Sorry.. I'm not good at all

Answer 29

Ok, so for part a, how would I change this? -3cos(2 x – pi/2).

Answer 30

same thing?

Answer 31

-3cos(2 x – 90).

Answer 32

If '-3cos(2 x – pi/2)' is correct, then it is correct

Answer 33

Ok:). so for problem a the answer is y=4(90 - 1/4 x )

Answer 34

I think so, I'm not sure

Answer 35

this is so strange, Icannot graph the equations

Answer 36

Ok, how do we solve the last question!

Answer 37

not !, but? sorry, lol

Answer 38

Little typo sounds so different. hahah

Answer 39

lol you can see I'm opening so many things at the same time.. I should hide it next time hehe~

Answer 40

lol.

Answer 41

Should I just use pi in my equations?

Answer 42

nope... pi =180 degrees... you need to change it

Answer 43

How do we solve the second one?

Answer 44

Time to graph again~ Please wait again :(

Answer 45

Ok, Il try it as well. Btw, thank you for your help:)

Answer 46

This one is easier :)

Answer 47

so for the first one,
a = 4 and b = pi/2 - 1/4

and for the second on,
a = -3, b = 2

Is this correct?

Answer 48

@callisto, is that correct?

Answer 49

Not really..

Answer 50

but those are the values for the equations

Answer 51

bx.....

Answer 52

pi/2,in which you should write 90, is a constant in the cosine function

Answer 53

But if replace pi/2 with 90, my graph changes

Answer 54

because .... the axis is different.....

Answer 55

I will get this instead

Answer 56

I know....but you need the answer in degrees, right?

Answer 57

Yes, so how can I have my answer in degree,while not ruining the graph?

Answer 58

You need to hand in the graph as well?

Answer 59

I think so

Answer 60

Hmm..hand in through computer?

Answer 61

what are the values of a and b in the first graph?

Answer 62

If my values are wrong, I need to know what the values are

Answer 63

I think you need to have a constant term... Can you?

Answer 64

What do you mean?

Answer 65

Let say, for first graph - question b
y=4(90 - 1/4 x )
y = a(c - bx)
a = 4, b=-1/4 and you 'll need a c

Answer 66

isnt c in this case 90 then>?

Answer 67

yes

Answer 68

Yes but the graph comes out like this
http://assets.openstudy.com/updates/attachments/4f8a3e36e4b09e61bffbf6a1-open2study-1334463738275-capture.png

Answer 69

It doesnt cross in 4 at the y-axis

Answer 70

x is not the angle... I'm confused:S!!!!

Answer 71

For the 1st graph, a = 4 and and b - ¼. A constant should be add in the functin, so it becomes y=asin(bx+c), where c = 90degrees(also equal to pi/2)Therefore, the equation is y = 4sin(90degrees – ¼ x)

Answer 72

Oh. ok, I see where I got it wrong. How about the 2nd graph?

Answer 73

@callisto?

Answer 74

It should be correct. Sorry :(

Answer 75

Ok. Thank you:) 1 more question for this assignment.

Answer 76

Okay!~ I have to be concentrated this time!!