Let’s solve each problem step by step. We’ll find the period, amplitude, reflection, phase shift, vertical shift, and list transformations in order for each sine function.
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Problem 1: y = (2/3) sin x
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Period: The parent function y = sin x has period 2π. Since there’s no coefficient inside the sine (like sin(bx)), b = 1 → Period = 2π / 1 =
2π
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Amplitude: The number in front is 2/3 → Amplitude =
2/3
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Reflection: No negative sign in front →
none
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Phase Shift: No horizontal shift (no “x - c” inside) →
none
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Vertical Shift: No constant added or subtracted at the end →
none
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Transformations: Only one transformation — vertical compression by factor of 2/3. So:
→ *Vertical compression by 2/3*
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Problem 2: y = 4 sin(πx)
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Period: Here, b = π → Period = 2π / π =
2
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Amplitude: Coefficient in front is 4 → Amplitude =
4
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Reflection: No negative sign →
none
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Phase Shift: Nothing added/subtracted to x inside →
none
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Vertical Shift: No constant at the end →
none
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Transformations: First, change the period (horizontal compression), then stretch vertically. Order matters!
→ *Horizontal compression so period becomes 2, then vertical stretch by 4*
Wait — let’s be precise about order. According to instructions: write transformations IN THE ORDER THEY OCCUR.
When you have y = A sin(Bx), you first apply the horizontal scaling (which affects period), then vertical scaling.
So:
→ *Horizontal compression by factor of 1/π (to get period 2), then vertical stretch by 4*
But since we usually describe it as “change period first”, and then amplitude, that’s fine.
Actually, standard order: horizontal changes first (inside the function), then vertical (outside). So:
→ *Change period to 2 (by compressing horizontally), then stretch vertically by 4*
We can say:
→ *Period changed to 2, then amplitude scaled to 4*
But to match worksheet style:
→ *Horizontal compression (period = 2), vertical stretch (amplitude = 4)*
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Problem 3: y = 2 sin(½x)
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Period: b = ½ → Period = 2π / (½) = 4π →
4π
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Amplitude: 2 →
2
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Reflection: No negative →
none
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Phase Shift: none →
none
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Vertical Shift: none →
none
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Transformations: Again, horizontal change first (stretch because b < 1), then vertical stretch.
→ *Horizontal stretch so period becomes 4π, then vertical stretch by 2*
Or:
→ *Period changed to 4π, then amplitude scaled to 2*
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Problem 4: y = sin x + 3
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Period: b = 1 → Period = 2π →
2π
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Amplitude: coefficient is 1 →
1
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Reflection: no negative →
none
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Phase Shift: none →
none
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Vertical Shift: +3 at the end →
up 3
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Transformations: Only vertical shift happens here.
→ *Shift graph up 3 units*
Note: Even though amplitude is 1, we still write it. And since no other changes, only vertical shift.
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Now, double-check all answers:
✔ Problem 1: All correct — just amplitude changed.
✔ Problem 2: Period = 2π/π = 2 ✔️, Amp = 4 ✔️, no shifts ✔️
✔ Problem 3: Period = 2π/(0.5) = 4π ✔️, Amp = 2 ✔️
✔ Problem 4: Vertical shift up 3 ✔️, everything else same as parent ✔️
All good!
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Final Answer:
1. y = (2/3) sin x
Period: 2π
Amplitude: 2/3
Reflection: none
Phase Shift: none
Vertical Shift: none
Transformations: Vertical compression by 2/3
2. y = 4 sin(πx)
Period: 2
Amplitude: 4
Reflection: none
Phase Shift: none
Vertical Shift: none
Transformations: Horizontal compression (period = 2), then vertical stretch by 4
3. y = 2 sin(½x)
Period: 4π
Amplitude: 2
Reflection: none
Phase Shift: none
Vertical Shift: none
Transformations: Horizontal stretch (period = 4π), then vertical stretch by 2
4. y = sin x + 3
Period: 2π
Amplitude: 1
Reflection: none
Phase Shift: none
Vertical Shift: up 3
Transformations: Shift graph up 3 units
Parent Tip: Review the logic above to help your child master the concept of graphs of sine and cosine functions worksheet.