# Homework Help: Trigonometric Functions - Confusing question

1. Nov 29, 2004

### Markd

What equation in the form y=sin(theta)+c best models the dtat in the chart below...
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(theta)radians : 1 : pi/2 : pi : 3pi/2 : 2pi
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y-------------: 2 :--3--:-2-:-1----:--2
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I am really confused on how to approach the problem, can someone please lend a hand?

Last edited: Nov 29, 2004
2. Nov 29, 2004

### Jameson

The normal sine curve goes like this:

X|0 pi/2 pi 3pi/2 2pi
Y|0 1 0 -1 0

It has a period of 2pi, meaning it takes that distance to make one cycle and then it repeats

So your graph starts at 2, then increases to 3, back to 2, down to 1, and finally back to 2.

Sound familiar?

It's just like the normal sine curve but shifted up 2 units.

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y = sinx + 2

3. Nov 29, 2004

### cdhotfire

I would guess you would supstitute for y and theta, but that doesnt seem to work, I also trying with a number in from of sin (theta) but that doesnt work either. Did you copy the problem correctly?

4. Nov 29, 2004

### Markd

the period is 2pi
a value is 1
c value is 2
no phase shift

I think I am going to write it in the form y=asin(x-d)+c

so would I write, sin2pi(x)+2 or sinx+2? or does it matter?

btw, I did copy it correctly cdhotfire

5. Nov 29, 2004

### cdhotfire

hehe, I wrote my response and then saw what jameson said, and i couldnt earase my awnser. :rofl:

6. Nov 29, 2004

### Jameson

you'd write y = sinx + 2

the period is a separate calculation

7. Nov 29, 2004

Thanks guys