Question

Which trigonometric function is equivalent to lower f left parenthesis x right parenthesis equals sine x?
(1 point)
Responses

lower f left parenthesis x right parenthesis equals cosine left parenthesis x minus start fraction 3 pi over 2 end fraction right parenthesis
Image with alt text: lower f left parenthesis x right parenthesis equals cosine left parenthesis x minus start fraction 3 pi over 2 end fraction right parenthesis

lower f left parenthesis x right parenthesis equals cosine left parenthesis x minus start fraction pi over 2 end fraction right parenthesis
Image with alt text: lower f left parenthesis x right parenthesis equals cosine left parenthesis x minus start fraction pi over 2 end fraction right parenthesis

lower f left parenthesis x right parenthesis equals cosine left parenthesis negative x minus start fraction pi over 2 end fraction right parenthesis
Image with alt text: lower f left parenthesis x right parenthesis equals cosine left parenthesis negative x minus start fraction pi over 2 end fraction right parenthesis

lower f left parenthesis x right parenthesis equals cosine left parenthesis x plus pi right parenthesis

Answers

GPT-4o mini
To determine which function is equivalent to \( f(x) = \sin x \), we can use the properties of sine and cosine functions, particularly their phase shifts.

The sine function can be expressed in terms of the cosine function with a phase shift. Specifically:

\[
\sin x = \cos\left(x - \frac{\pi}{2}\right)
\]

This means that sine can be rewritten as the cosine of an angle shifted by \(-\frac{\pi}{2}\).

Now let's analyze the responses:

1. \( f(x) = \cos\left(x - \frac{3\pi}{2}\right) \)
- This is not equivalent to \( \sin x \).

2. \( f(x) = \cos\left(x - \frac{\pi}{2}\right) \)
- This is equivalent to \( \sin x \).

3. \( f(x) = \cos\left(-x - \frac{\pi}{2}\right) \)
- This is not equivalent to \( \sin x \).

4. \( f(x) = \cos(x + \pi) \)
- This is equal to \(-\cos x\), which is also not equivalent to \( \sin x \).

The correct answer is:

**\( f(x) = \cos\left(x - \frac{\pi}{2}\right) \)**

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