Exponential Derivatives 42429B
1. **Problem Statement:** Find the first, second, and third derivatives of the functions:
i. $y(x) = e^{6x^2 + 3x - 2}$
ii. $y(x) = e^{3x - 2}$
iii. $y(x) = e^{kx}$
2. **Formula and Rules:**
The derivative of $e^{u(x)}$ with respect to $x$ is given by the chain rule:
$$\frac{dy}{dx} = e^{u(x)} \cdot u'(x)$$
For higher order derivatives, apply the product and chain rules repeatedly.
3. **Solution for i. $y = e^{6x^2 + 3x - 2}$:**
- Let $u = 6x^2 + 3x - 2$
- Then $u' = 12x + 3$
**First derivative:**
$$y' = e^{u} \cdot u' = e^{6x^2 + 3x - 2} (12x + 3)$$
**Second derivative:**
Apply product rule:
$$y'' = \frac{d}{dx}[e^{u}(12x + 3)] = e^{u} u' (12x + 3) + e^{u} (12) = e^{6x^2 + 3x - 2} [(12x + 3)^2 + 12]$$
**Third derivative:**
Again, differentiate $y''$:
$$y''' = \frac{d}{dx} \left(e^{u} [(12x + 3)^2 + 12] \right)$$
Using product rule:
$$y''' = e^{u} u' [(12x + 3)^2 + 12] + e^{u} \cdot 2(12x + 3)(12)$$
Simplify:
$$y''' = e^{6x^2 + 3x - 2} \left[(12x + 3)^3 + 12(12x + 3) + 24(12x + 3) \right] = e^{6x^2 + 3x - 2} \left[(12x + 3)^3 + 36(12x + 3) \right]$$
4. **Solution for ii. $y = e^{3x - 2}$:**
- Let $u = 3x - 2$
- Then $u' = 3$
**First derivative:**
$$y' = e^{3x - 2} \cdot 3 = 3 e^{3x - 2}$$
**Second derivative:**
$$y'' = \frac{d}{dx} (3 e^{3x - 2}) = 3 \cdot 3 e^{3x - 2} = 9 e^{3x - 2}$$
**Third derivative:**
$$y''' = \frac{d}{dx} (9 e^{3x - 2}) = 9 \cdot 3 e^{3x - 2} = 27 e^{3x - 2}$$
5. **Solution for iii. $y = e^{kx}$:**
- Let $u = kx$
- Then $u' = k$
**First derivative:**
$$y' = e^{kx} \cdot k = k e^{kx}$$
**Second derivative:**
$$y'' = \frac{d}{dx} (k e^{kx}) = k^2 e^{kx}$$
**Third derivative:**
$$y''' = \frac{d}{dx} (k^2 e^{kx}) = k^3 e^{kx}$$
**Summary:**
- For $y = e^{6x^2 + 3x - 2}$, derivatives involve chain and product rules with polynomial factors.
- For $y = e^{3x - 2}$, derivatives scale by powers of 3.
- For $y = e^{kx}$, the $n$th derivative is $k^n e^{kx}$.
This matches the program logic where the $n$th derivative of $e^{ax}$ is $a^n e^{ax}$.