1. **Problem:** Differentiate the following functions with respect to $x$:
d) $y = (2x^2 - 5)^9$
e) $y = \frac{(2x + 1)^6}{3}$
g) $y = 6(5 - x)^5$
h) $y = \frac{1}{(2x + 5)^8}$
2. **Formula and rules:**
Use the chain rule for differentiation: If $y = [f(x)]^n$, then
$$\frac{dy}{dx} = n[f(x)]^{n-1} \cdot f'(x)$$
For a constant multiple $c$, $\frac{d}{dx}[c \cdot g(x)] = c \cdot g'(x)$.
For $y = \frac{1}{u(x)} = u(x)^{-1}$, use the power rule and chain rule.
3. **Step-by-step differentiation:**
d) $y = (2x^2 - 5)^9$
- Inner function: $u = 2x^2 - 5$
- Derivative of inner function: $u' = 4x$
- Apply chain rule:
$$\frac{dy}{dx} = 9(2x^2 - 5)^8 \cdot 4x = 36x(2x^2 - 5)^8$$
e) $y = \frac{(2x + 1)^6}{3} = \frac{1}{3}(2x + 1)^6$
- Inner function: $u = 2x + 1$
- Derivative of inner function: $u' = 2$
- Apply chain rule:
$$\frac{dy}{dx} = \frac{1}{3} \cdot 6(2x + 1)^5 \cdot 2 = \frac{12}{3}(2x + 1)^5 = 4(2x + 1)^5$$
g) $y = 6(5 - x)^5$
- Inner function: $u = 5 - x$
- Derivative of inner function: $u' = -1$
- Apply chain rule:
$$\frac{dy}{dx} = 6 \cdot 5(5 - x)^4 \cdot (-1) = -30(5 - x)^4$$
h) $y = \frac{1}{(2x + 5)^8} = (2x + 5)^{-8}$
- Inner function: $u = 2x + 5$
- Derivative of inner function: $u' = 2$
- Apply chain rule:
$$\frac{dy}{dx} = -8(2x + 5)^{-9} \cdot 2 = -16(2x + 5)^{-9} = -\frac{16}{(2x + 5)^9}$$
4. **Final answers:**
d) $\boxed{36x(2x^2 - 5)^8}$
e) $\boxed{4(2x + 1)^5}$
g) $\boxed{-30(5 - x)^4}$
h) $\boxed{-\frac{16}{(2x + 5)^9}}$
Diff Powers 4B6A09
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