Which function has the given properties below?

- The domain is the set of all real numbers.
- One [tex]\( x \)[/tex]-intercept is [tex]\(\left(\frac{\pi}{2}, 0\right)\)[/tex].
- The maximum value is 3.
- The [tex]\( y \)[/tex]-intercept is [tex]\((0, -3)\)[/tex].

A. [tex]\( y = -3 \sin(x) \)[/tex]
B. [tex]\( y = -3 \cos(x) \)[/tex]
C. [tex]\( y = 3 \sin(x) \)[/tex]
D. [tex]\( y = 3 \cos(x) \)[/tex]



Answer :

We are given the following properties for a function and need to identify which of the four provided functions meets these criteria.

1. The domain is the set of all real numbers.
2. One [tex]\( x \)[/tex]-intercept is [tex]\(\left(\frac{\pi}{2}, 0\right)\)[/tex].
3. The maximum value is 3.
4. The [tex]\( y \)[/tex]-intercept is [tex]\((0, -3)\)[/tex].

Let's analyze each function step-by-step according to the given properties.

### Option 1: [tex]\( y = -3 \sin(x) \)[/tex]

1. Domain: The sine function is defined for all real numbers, so this criterion is met.
2. [tex]\(x\)[/tex]-intercept: When [tex]\( x = \frac{\pi}{2} \)[/tex]:
[tex]\[ y = -3 \sin\left(\frac{\pi}{2}\right) = -3 \cdot 1 = -3 \][/tex]
This does not give us [tex]\((\frac{\pi}{2}, 0)\)[/tex].
3. Maximum value: The maximum value of [tex]\(-3 \sin(x)\)[/tex] occurs when [tex]\(\sin(x) = -1\)[/tex]:
[tex]\[ \max = -3 \times -1 = 3 \][/tex]
This criterion is met.
4. [tex]\(y\)[/tex]-intercept: When [tex]\( x = 0 \)[/tex]:
[tex]\[ y = -3 \sin(0) = -3 \cdot 0 = 0 \][/tex]
The [tex]\( y \)[/tex]-intercept is [tex]\((0, 0)\)[/tex], not [tex]\((0, -3)\)[/tex].

Therefore, [tex]\( y = -3 \sin(x) \)[/tex] does not meet all the given properties.

### Option 2: [tex]\( y = -3 \cos(x) \)[/tex]

1. Domain: The cosine function is defined for all real numbers, so this criterion is met.
2. [tex]\(x\)[/tex]-intercept: When [tex]\( x = \frac{\pi}{2} \)[/tex]:
[tex]\[ y = -3 \cos\left(\frac{\pi}{2}\right) = -3 \cdot 0 = 0 \][/tex]
This gives the correct [tex]\( x \)[/tex]-intercept [tex]\( \left(\frac{\pi}{2}, 0\right) \)[/tex].
3. Maximum value: The maximum value of [tex]\(-3 \cos(x)\)[/tex] occurs when [tex]\(\cos(x) = -1\)[/tex]:
[tex]\[ \max = -3 \times -1 = 3 \][/tex]
This criterion is met.
4. [tex]\(y\)[/tex]-intercept: When [tex]\( x = 0 \)[/tex]:
[tex]\[ y = -3 \cos(0) = -3 \cdot 1 = -3 \][/tex]
The [tex]\( y \)[/tex]-intercept is [tex]\((0, -3)\)[/tex].

Thus, [tex]\( y = -3 \cos(x) \)[/tex] meets all the given properties.

### Option 3: [tex]\( y = 3 \sin(x) \)[/tex]

1. Domain: The sine function is defined for all real numbers, so this criterion is met.
2. [tex]\(x\)[/tex]-intercept: When [tex]\( x = \frac{\pi}{2} \)[/tex]:
[tex]\[ y = 3 \sin\left(\frac{\pi}{2}\right) = 3 \times 1 = 3 \][/tex]
This does not give us [tex]\((\frac{\pi}{2}, 0)\)[/tex].
3. Maximum value: The maximum value of [tex]\(3 \sin(x)\)[/tex] occurs when [tex]\(\sin(x) = 1\)[/tex]:
[tex]\[ \max = 3 \times 1 = 3 \][/tex]
This criterion is met.
4. [tex]\(y\)[/tex]-intercept: When [tex]\( x = 0 \)[/tex]:
[tex]\[ y = 3 \sin(0) = 3 \times 0 = 0 \][/tex]
The [tex]\( y \)[/tex]-intercept is [tex]\((0, 0)\)[/tex], not [tex]\((0, -3)\)[/tex].

Therefore, [tex]\( y = 3 \sin(x) \)[/tex] does not meet all the given properties.

### Option 4: [tex]\( y = 3 \cos(x) \)[/tex]

1. Domain: The cosine function is defined for all real numbers, so this criterion is met.
2. [tex]\(x\)[/tex]-intercept: When [tex]\( x = \frac{\pi}{2} \)[/tex]:
[tex]\[ y = 3 \cos\left(\frac{\pi}{2}\right) = 3 \cdot 0 = 0 \][/tex]
This gives the correct [tex]\( x \)[/tex]-intercept [tex]\( \left(\frac{\pi}{2}, 0\right) \)[/tex].
3. Maximum value: The maximum value of [tex]\(3 \cos(x)\)[/tex] occurs when [tex]\(\cos(x) = 1\)[/tex]:
[tex]\[ \max = 3 \times 1 = 3 \][/tex]
This criterion is met.
4. [tex]\(y\)[/tex]-intercept: When [tex]\( x = 0 \)[/tex]:
[tex]\[ y = 3 \cos(0) = 3 \cdot 1 = 3 \][/tex]
The [tex]\( y \)[/tex]-intercept is [tex]\((0, 3)\)[/tex], not [tex]\((0, -3)\)[/tex].

Therefore, [tex]\( y = 3 \cos(x) \)[/tex] does not meet all the given properties.

### Conclusion
None of the functions meets all the specified properties, hence none of the given functions match the criteria.