Derivative Csc Cot
1. **State the problem:** Find the derivative $f'(x)$ of the function $f(x) = \csc x \cot x$.
2. **Recall the formulas and rules:**
- The derivative of $\csc x$ is $-\csc x \cot x$.
- The derivative of $\cot x$ is $-\csc^2 x$.
- Use the product rule: If $f(x) = u(x)v(x)$, then $f'(x) = u'(x)v(x) + u(x)v'(x)$.
3. **Apply the product rule:**
Let $u = \csc x$ and $v = \cot x$.
Then,
$$
f'(x) = u'v + uv' = (-\csc x \cot x)(\cot x) + (\csc x)(-\csc^2 x)
$$
4. **Simplify each term:**
$$
(-\csc x \cot x)(\cot x) = -\csc x \cot^2 x
$$
$$
(\csc x)(-\csc^2 x) = -\csc^3 x
$$
5. **Combine the terms:**
$$
f'(x) = -\csc x \cot^2 x - \csc^3 x
$$
6. **Factor out common terms:**
$$
f'(x) = -\csc x (\cot^2 x + \csc^2 x)
$$
7. **Use the Pythagorean identity:**
Recall that $\cot^2 x + 1 = \csc^2 x$, so
$$
\cot^2 x + \csc^2 x = \cot^2 x + (\cot^2 x + 1) = 2\cot^2 x + 1
$$
Thus,
$$
f'(x) = -\csc x (2\cot^2 x + 1)
$$
**Final answer:**
$$
f'(x) = -\csc x (2\cot^2 x + 1)
$$