Derivative Inverse Sine Cosine
1. **State the problem:** We need to find the derivative of the function $$y = \sin^{-1}\left(\cos(2x^3 - 3x - 5)\right).$$
2. **Recall the derivative formula:** If $$y = \sin^{-1}(u)$$ then $$\frac{dy}{dx} = \frac{1}{\sqrt{1-u^2}} \cdot \frac{du}{dx}.$$ Here, $$u = \cos(2x^3 - 3x - 5).$$
3. **Find $$\frac{du}{dx}$$:**
$$u = \cos(2x^3 - 3x - 5)$$
Using the chain rule,
$$\frac{du}{dx} = -\sin(2x^3 - 3x - 5) \cdot \frac{d}{dx}(2x^3 - 3x - 5).$$
4. **Compute $$\frac{d}{dx}(2x^3 - 3x - 5)$$:**
$$\frac{d}{dx}(2x^3) = 6x^2,$$
$$\frac{d}{dx}(-3x) = -3,$$
$$\frac{d}{dx}(-5) = 0,$$
so,
$$\frac{d}{dx}(2x^3 - 3x - 5) = 6x^2 - 3.$$
5. **Therefore,**
$$\frac{du}{dx} = -\sin(2x^3 - 3x - 5)(6x^2 - 3).$$
6. **Substitute back into the derivative formula:**
$$\frac{dy}{dx} = \frac{1}{\sqrt{1 - \cos^2(2x^3 - 3x - 5)}} \cdot [-\sin(2x^3 - 3x - 5)(6x^2 - 3)].$$
7. **Simplify the square root term:**
Recall that $$\sin^2 \theta + \cos^2 \theta = 1,$$
so
$$1 - \cos^2(\alpha) = \sin^2(\alpha).$$
Thus,
$$\sqrt{1 - \cos^2(2x^3 - 3x - 5)} = |\sin(2x^3 - 3x - 5)|.$$
8. **Final expression:**
$$\frac{dy}{dx} = \frac{-\sin(2x^3 - 3x - 5)(6x^2 - 3)}{|\sin(2x^3 - 3x - 5)|} = -(6x^2 - 3) \frac{\sin(2x^3 - 3x - 5)}{|\sin(2x^3 - 3x - 5)|}.$$
9. **Interpreting the fraction:**
The fraction $$\frac{\sin(\theta)}{|\sin(\theta)|}$$ is the sign of $$\sin(\theta)$$, denoted $$\operatorname{sgn}(\sin(\theta))$$.
So,
$$\frac{dy}{dx} = -(6x^2 - 3) \operatorname{sgn}(\sin(2x^3 - 3x - 5)).$$
**Answer:**
$$\boxed{\frac{dy}{dx} = -(6x^2 - 3) \operatorname{sgn}(\sin(2x^3 - 3x - 5))}.$$