Question

PRECALC quiz help!! question !! not sure if my two answers are right but i need all the answers if anyone can hellpp

Answer 1

Ok, well, how are sine waves oriented with the origin (0,0)? Hint: what is sin 0?
That x should give you an idea of how much the graph has shifted horizontally (phase shift).

Answer 2

Your other two answers are looking good.

Answer 3

sine of 0 is 0

Answer 4

so that means that the graph shown right now isn't matching with the sine wave, right? how many units do you have to move it for the wave to intersect (0,0) and in what direction?

Answer 5

three units to the left?

Answer 6

yep, so considering that the equation is y = a sin (bx+c), and that c indicates horizontal movement, and positive c goes to the left, how much can you fill in?

Answer 7

umm i know it starts 6sin(bx+c) i know that c is going to be +12 but thats all i can figure out?

Answer 8

this one is tough and it says c is the least positive real number?

Answer 9

hmm, I'm gonna think about this a little longer then. I thought I had it :(

Answer 10

thanks for trying i really appreciate it, let me know if you get it or something !!!!!!

Answer 11

haha, no problem, that's what this site is, isn't it? I'm just surprised that no one here tackled your question before me.

Answer 12

Ok, I've been trying a couple of things and this is what I've got:
First, you're right that a=6. But that's the easy part.
You knew the period was 12 because that's how long a "cycle" was, right? The formal formula (pun intended) for calculating the period is \[2\pi \over |b|\] So you can solve for b.

Answer 13

pi/6 = b?

Answer 14

Yeah, good job! To find c is a bit trickier. I'm gonna explain it in a bit of a roundabout way, so bear with me. Ok, whenever we have a graph that is not centered at (0,0), you have to add something to the x in the "original" (parent) equation. Our equation was y = a sin (bx+c). The graph is shifted, as you've said earlier, 3 to the left. Ignore what I said earlier about it.

Answer 15

wouldnt it be x + 3? if moving to left cause its in ()

Answer 16

Whoa, chrome logged out on me. Sorry for the delay.
No, it should be (x-3). And that's because I confirmed you wrongly in the first place. Sorry. Ok, the confusion was that the graph was shifted 3 to the left. Actually, it's shifted 3 to the right. I'm going to erase my last post to help clear things up. From the beginning, then: a=6 and b=pi/6 so y = 6 sin (pi/6(x-3)). Am I making this confusing?

Answer 17

Uh, I got to go. This is what I've got:
y = 6 sin [(pi/6)x - 3(pi/6)]
y = 6 sin [(pi/6)x - (pi/2)]
so c = -(pi/2)
but you want a positive c. So just make 6 negative and c positive. So
y = -6 sin [(pi/6)x + (pi/2)]
I checked it. It works on my calculator

Answer 18

wombat this is what i have, i have half of it right.. any help?

Answer 19

lets see... phase shift is the horizontal shift so the graph has moved 3 units to the right. So the phase shift should be period divided by b...so 12/b

Answer 20

umm the question also says it has a positive coefficient so your equation can't be right cuza the negative...

Answer 21

oi haven't done this in a long time..

Answer 22

it should start out with 6sin(...)

sorry im doing bits and pieces

Answer 23

dont say sorry your a major help

Answer 24

12/b is 12/pi/6 which is 12*6/pi which is like 72/pi i dont think thats the phase shift tho ya know? phase shift is c/b so is it *(from my current equation) c/b= pi/2 / 12 = ?

Answer 25

that was prolly really confusing/ wrong lol and thanks!!

Answer 26

where do you attend school?

Answer 27

oh shnikes! phase shift = c/b...

Answer 28

b=pi/6 i think

Answer 29

since period = 2pi/b, b=2pi/period -> b=2pi/12=pi/6

Answer 30

so is that my phase shift pi/6?

Answer 31

no phase shift is the c value...workin on it. almost have it graphed

Answer 32

kkk

Answer 33

YAY! it is 6sin((pi/6)x-(pi/2)) for the equation
phase shift is c/b which is (pi/2)/(pi/6) which i think comes out to 3/2

Answer 34

DONT SUBMIT YET lemme double check

Answer 35

Yea i think thats right

Answer 36

how old are ya wombat if ya dont mind me asking/ and where ya from and stuff?

Answer 37

Haha all that I will say is below drinking age :P

Answer 38

dang nice! i go to UGA i waited till last second to learn this stuff. and well my teacher is russian and i cant understand a word spoken lol

Answer 39

Haha that stinks XD

Answer 40

yuuuuuuuuuuuuuup

Answer 41

i noticed the only question uve asked is a chem question huh? i hate chem

Answer 42

haha yeah...that was when i first came here. then turns out someone else had asked the exact same thing

Answer 43

dang!! i missed it again ahh i think i just wrote it wrong or something?

Answer 44

see

Answer 45

heres an example of my friends

Answer 46

...i put that in my graphing calculator and it worked out perfectly... i don't get it...maybe they wanted it as (x*pi / 6)? ugh i hate computer tests

Answer 47

and the phase shift...i guess my only other suggestion would be to try 3

Answer 48

but he got the last part wrong too, i think i just wrote the last part wrong or the dumb computer isnt reading it correctly or something :( but any idea how i should retry the phase shift part? maybe just put in (pi/2)/(pi/6) instead of 3/2*** ohh its 3 not 3/2!!

Answer 49

D*** it yes its 3...

Answer 50

that was my fault sorry

Answer 51

wow i can't divide fractions...thats just sad...

Answer 52

they still didnt like it what fools! i cant wait to see what the "correct answer" is later lol , ill let you know when i find out at 12

Answer 53

thanks for ALL your help your awesome, i wish you could take the quiz for me wed
lol

Answer 54

im not awesome... i just screwed up (pi/2)/(pi/6)...