Function Parity Derivative
1. **Problem statement:**
Determine if the function $g(f(x))$ where $f(x)=x^3+2$ and $g(x)=\cos x$ is even, odd, or neither.
2. **Recall definitions:**
- A function $h(x)$ is **even** if $h(-x) = h(x)$ for all $x$.
- A function $h(x)$ is **odd** if $h(-x) = -h(x)$ for all $x$.
3. **Evaluate $g(f(-x))$:**
$$g(f(-x)) = g((-x)^3 + 2) = g(-x^3 + 2) = \cos(-x^3 + 2)$$
4. **Evaluate $g(f(x))$:**
$$g(f(x)) = g(x^3 + 2) = \cos(x^3 + 2)$$
5. **Check if $g(f(x))$ is even:**
Is $\cos(-x^3 + 2) = \cos(x^3 + 2)$?
Since cosine is an even function, $\cos(-\theta) = \cos(\theta)$, but here the arguments differ by more than just a sign because of the $+2$ term.
6. **Check if $g(f(x))$ is odd:**
Is $\cos(-x^3 + 2) = -\cos(x^3 + 2)$?
No, cosine values are not negated by changing the sign inside the argument plus a constant.
7. **Conclusion:**
Since neither condition holds, $g(f(x))$ is **neither even nor odd**.
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**Part b) Derivative of $\sqrt{2}$ from first principles:**
1. **Problem statement:**
Find the derivative of the constant function $h(x) = \sqrt{2}$ using first principles.
2. **Recall definition of derivative from first principles:**
$$h'(x) = \lim_{h \to 0} \frac{h(x+h) - h(x)}{h}$$
3. **Apply to $h(x) = \sqrt{2}$:**
$$h'(x) = \lim_{h \to 0} \frac{\sqrt{2} - \sqrt{2}}{h} = \lim_{h \to 0} \frac{0}{h} = 0$$
4. **Explanation:**
Since $\sqrt{2}$ is a constant, its derivative is zero everywhere.
**Final answers:**
- $g(f(x))$ is neither even nor odd.
- The derivative of $\sqrt{2}$ is $0$.