Question

What is the phase shift of this graph? I can't seem to find it. It's not -1, 1, -2, or 2...

Answer 1

its not phase shifted .... which is a way to say that its been moved left or right

Answer 2

it has been squished; -2cos(x) is periodic every 2pi, this one seems to be periodic at 4

Answer 3

So it has no phase shift? Because it's not taking no phase shift as an answer, either...

Answer 4

http://www.wolframalpha.com/input/?i=y%3D-2cos%28x*pi%2F2%29

Answer 5

cosine and sine are phase shifts of each other, so it may want you to express it in terms of sin

Answer 6

It does... I'm not exactly sure how to do that

Answer 7

Sorry, I should've mentioned that this was a sin graph earlier

Answer 8

cos(x) = sin(x+pi/2)

cos(x*pi/2) = sin(x*pi/2+pi/2)

sin(pi/2 (x+1))

http://www.wolframalpha.com/input/?i=y%3D-2cos%28x*pi%2F2%29%2C+-2sin%28pi%2F2+%28x%2B1%29%29

shifted left by 1 seems good

Answer 9

It's still not accepting that...

Answer 10

take a screen shot of the page .... maybe theres something about the answer format that they are expecting.

Answer 11

For all my other questions that phase shift has work so Idk what's up with this one...

Answer 12

try: -pi/2

Answer 13

I've also tried plugging in the sine formula for the next part and it won't take that either

I'll try that

Answer 14

Still not taking it...

Answer 15

there seems to be some ambiguity:

A sin(Bx - C), when B=1, C is called the phase shift

however, Physicists and engineers say that regardless of the value of B, C is the phase shift

Answer 16

sin [x*pi/2- (-pi/2) ]
B C


sin [pi/2 (x- (-1) ]
B C

try a positive pi/2 ?

Answer 17

Tried :(

Answer 18

the only other idea i have is to yell and swear .... maybe hit something :/

Answer 19

do they expect the phase shift to be the smallest value? or is direction important?

Answer 20

try 2pi

Answer 21

"the only other idea i have is to yell and swear .... maybe hit something :/" <- best response

Answer 22

I have no idea... I always try both positive and negatives (though it usually accepts the negative more often)

Answer 23

It also lags when you submit an answer (which is sadly normal) which is why Idk if that works yet

Answer 24

Nope... doesn't accept 2pi or -2pi

Answer 25

the smallest postive real number

Answer 26

Do you want to give up on this one? I thought I was just doing something wrong but now it's starting to seem ridiculous lol

Answer 27

well, i know i got the correct writeup:

\[y = -2~\sin(\frac{\pi}{2}x+\frac{\pi}{2})\]
http://www.wolframalpha.com/input/?i=y%3D-2sin%28x*pi%2F2%2Bpi%2F2%29
but they say A is postive, and so is B

-sin(x) = sin(-x)

\[y = 2~\sin(-[\frac{\pi}{2}x+\frac{\pi}{2}])\]
\[y = 2~\sin(-\frac{\pi}{2}x-\frac{\pi}{2})\]

yeah, this is getting rediculous .. confounding programs :/

Answer 28

It's not accepting anything ><

Answer 29

sin(x)

sin(x*pi/2)

2sin(x*pi/2)

2sin(x*pi/2+3pi/2)

that seems to match the expected criteria http://www.wolframalpha.com/input/?i=2+sin%28x*pi%2F2%2B3pi%2F2%29%2C

try a phase shift of say: -3, or 3pi/2

Answer 30

other than that ... im out of ideas for this. Programs are not spose to make learning this complicated :/

Answer 31

-3!!!!!!!

Answer 32

i take it that worked ...

Answer 33

Yes!!!! Thank you so much!!! :D

Answer 34

lol ... oy that was like pulling teeth! good luck ;)

Answer 35

Thanks :) You're amazing!