Math Problem Statement

Graph y = 3 sin 2(x − 45◦) + 4, and describe it’s relationship to y = sin x.

Graph y = 3 sin 2(x − 45°) + 4, and describe its relationship to y = sin x.

Solution

The graph shows two trigonometric functions:

  1. Red Curve: y=sin(x)y = \sin(x)
  2. Blue Curve: y=3sin(2(x45))+4y = 3 \sin(2(x - 45^\circ)) + 4

Let's break down and compare these two functions:

y=sin(x)y = \sin(x) (Red Curve):

  • This is the basic sine wave with:
    • Amplitude: 1
    • Period: 2π2\pi radians (or 360°)
    • No phase shift or vertical shift.

y=3sin(2(x45))+4y = 3 \sin(2(x - 45^\circ)) + 4 (Blue Curve):

  • This is a transformed sine function, which undergoes several changes:
    1. Amplitude: The coefficient "3" increases the amplitude to 3. So, the wave peaks at 3 and valleys at -3 (before the vertical shift).
    2. Frequency: The coefficient "2" inside the sine argument affects the frequency. The period is now 3602=180\frac{360^\circ}{2} = 180^\circ. So, the wave completes one cycle in 180°.
    3. Phase Shift: The term (x45)(x - 45^\circ) shifts the graph 45° to the right.
    4. Vertical Shift: The "+4" moves the entire wave 4 units upward.

Relationship:

  • Amplitude Change: The blue curve is taller (amplitude of 3) compared to the red curve (amplitude of 1).
  • Frequency Change: The blue curve has a shorter period of 180° (double the frequency of the red curve).
  • Phase Shift: The blue curve is shifted 45° to the right.
  • Vertical Shift: The blue curve is shifted 4 units up, so its centerline is at y=4y = 4 instead of the x-axis.

Summary:

  • The blue curve represents a sine function that oscillates faster (double frequency), with higher peaks (amplitude 3), is shifted both vertically (up by 4 units) and horizontally (to the right by 45°).

Would you like further details on how these transformations affect the graph, or clarification on any of the terms used?


Related Questions:

  1. How do you calculate the period of a trigonometric function with frequency modifications?
  2. What would happen if you changed the phase shift to x+45x + 45^\circ?
  3. How does the vertical shift affect the maximum and minimum points of the sine wave?
  4. What are the real-world applications of trigonometric transformations like these?
  5. How do cosine and sine transformations compare visually?

Tip:

To determine the period of a sine or cosine function y=Asin(B(xC))+Dy = A \sin(B(x - C)) + D, use the formula Period=360B\text{Period} = \frac{360^\circ}{|B|} or 2πB\frac{2\pi}{|B|} in radians.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Graph Transformations
Sine Functions

Formulas

y = A sin(B(x - C)) + D
Period = 360° / |B|

Theorems

Trigonometric Transformations

Suitable Grade Level

Grades 10-12