Cosine 2025Th Derivative
1. **State the problem:** We need to find the 2025th derivative of the function $g(x) = \cos(x)$.
2. **Recall the derivatives of cosine:**
The derivatives cycle every 4 steps:
$g'(x) = -\sin(x)$
$g''(x) = -\cos(x)$
$g^{(3)}(x) = \sin(x)$
$g^{(4)}(x) = \cos(x)$ (back to the original function)
3. **Determine the remainder when 2025 is divided by 4:**
$$2025 \div 4 = 506 \text{ remainder } 1$$
This means the 2025th derivative has the same form as the first derivative in the cycle.
4. **Identify the 1st derivative function:**
$g'(x) = -\sin(x)$
5. **Conclusion:**
The 2025th derivative is $g^{(2025)}(x) = -\sin(x)$, which corresponds to option B.
**Final answer:** B) $-\sin(x)$