If `f(r,theta)=rcostheta,` then `f(2,3)`=

Options

A. `-3.00`
B. `-1.98`
C. `0.10`
D. `1.25`

Explanation

To solve the problem, we need to evaluate the function \( f(r, \theta) = r \cos(\theta) \) at the point \( (2, 3) \).

### Step-by-step Solution:

1. **Identify the function and the values**:
We have the function defined as:
\[ f(r, \theta) = r \cos(\theta) \]
We need to evaluate this function at \( r = 2 \) and \( \theta = 3 \).

2. **Substitute the values into the function**:
Substitute \( r = 2 \) and \( \theta = 3 \) into the function:
\[ f(2, 3) = 2 \cos(3) \]

3. **Calculate \( \cos(3) \)**:
Since \( 3 \) is in radians, we can use a calculator to find \( \cos(3) \).
\[ \cos(3) \approx -0.989992 \]

4. **Multiply by \( r \)**:
Now, substitute \( \cos(3) \) back into the function:
\[ f(2, 3) = 2 \times (-0.989992) \approx -1.979984 \]

5. **Round the result**:
Rounding the result gives:
\[ f(2, 3) \approx -1.98 \]

### Final Answer:
Thus, the value of \( f(2, 3) \) is approximately:
\[ \boxed{-1.98} \]