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Ch. 2 - Graphs of the Trigonometric Functions; Inverse Trigonometric Functions
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601당신이 사용하는 게 아니라요?교과서 변경
2장, 문제 23

In Exercises 17–30, determine the amplitude, period, and phase shift of each function. Then graph one period of the function. y = 1/2 sin(x + π/2)

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Identify the general form of the sine function: \(y = A \sin(B(x - C))\), where \(A\) is the amplitude, \(\frac{2\pi}{B}\) is the period, and \(C\) is the phase shift.
Rewrite the given function \(y = \frac{1}{2} \sin(x + \frac{\pi}{2})\) in the form \(y = A \sin(B(x - C))\). Notice that \(x + \frac{\pi}{2}\) can be written as \(x - (-\frac{\pi}{2})\), so \(C = -\frac{\pi}{2}\).
Determine the amplitude \(A\) by looking at the coefficient in front of the sine function. Here, \(A = \frac{1}{2}\), which means the graph oscillates between \(\frac{1}{2}\) and \(-\frac{1}{2}\).
Find the period by identifying \(B\). Since the function is \(\sin(x)\), \(B = 1\), so the period is \(\frac{2\pi}{B} = 2\pi\).
Determine the phase shift \(C\), which is \(-\frac{\pi}{2}\). This means the graph is shifted to the left by \(\frac{\pi}{2}\). Use this information to sketch one full period of the sine wave starting at \(x = -\frac{\pi}{2}\).

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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Amplitude of a Trigonometric Function

Amplitude is the maximum absolute value of a sine or cosine function, representing the height from the midline to the peak. For y = (1/2) sin(x + π/2), the amplitude is 1/2, indicating the wave oscillates between -1/2 and 1/2.
추천 영상:
6:04
Introduction to Trigonometric Functions

Period of a Sine Function

The period is the length of one complete cycle of the sine wave, calculated as 2π divided by the coefficient of x inside the function. Since the coefficient of x is 1 here, the period is 2π, meaning the function repeats every 2π units.
추천 영상:
5:33
Period of Sine and Cosine Functions

Phase Shift in Trigonometric Functions

Phase shift is the horizontal translation of the graph, determined by solving inside the function for zero. For y = (1/2) sin(x + π/2), the phase shift is -π/2, meaning the graph shifts π/2 units to the left.
추천 영상:
6:31
Phase Shifts