Derivative Quotient Bb69A0
1. **State the problem:** Find the derivative of the function $$y = \frac{5x^4 + 3x - 5 + 2}{x^3 + \pi x}$$.
2. **Recall the formula:** For a function $$y = \frac{u(x)}{v(x)}$$, the derivative is given by the quotient rule:
$$
\frac{dy}{dx} = \frac{v(x) u'(x) - u(x) v'(x)}{[v(x)]^2}
$$
where $$u(x) = 5x^4 + 3x - 3$$ (since $$-5 + 2 = -3$$) and $$v(x) = x^3 + \pi x$$.
3. **Find the derivatives of numerator and denominator:**
- $$u'(x) = \frac{d}{dx}(5x^4 + 3x - 3) = 20x^3 + 3$$
- $$v'(x) = \frac{d}{dx}(x^3 + \pi x) = 3x^2 + \pi$$
4. **Apply the quotient rule:**
$$
\frac{dy}{dx} = \frac{(x^3 + \pi x)(20x^3 + 3) - (5x^4 + 3x - 3)(3x^2 + \pi)}{(x^3 + \pi x)^2}
$$
5. **Expand the numerator:**
- First term:
$$
(x^3)(20x^3) = 20x^6
$$
$$
(x^3)(3) = 3x^3
$$
$$
(\pi x)(20x^3) = 20\pi x^4
$$
$$
(\pi x)(3) = 3\pi x
$$
Sum first term: $$20x^6 + 3x^3 + 20\pi x^4 + 3\pi x$$
- Second term:
$$
(5x^4)(3x^2) = 15x^6
$$
$$
(5x^4)(\pi) = 5\pi x^4
$$
$$
(3x)(3x^2) = 9x^3
$$
$$
(3x)(\pi) = 3\pi x
$$
$$
(-3)(3x^2) = -9x^2
$$
$$
(-3)(\pi) = -3\pi
$$
Sum second term: $$15x^6 + 5\pi x^4 + 9x^3 + 3\pi x - 9x^2 - 3\pi$$
6. **Subtract second term from first term:**
$$
(20x^6 + 3x^3 + 20\pi x^4 + 3\pi x) - (15x^6 + 5\pi x^4 + 9x^3 + 3\pi x - 9x^2 - 3\pi)
$$
$$
= (20x^6 - 15x^6) + (3x^3 - 9x^3) + (20\pi x^4 - 5\pi x^4) + (3\pi x - 3\pi x) + 9x^2 + 3\pi
$$
$$
= 5x^6 - 6x^3 + 15\pi x^4 + 0 + 9x^2 + 3\pi
$$
7. **Write the final derivative:**
$$
\frac{dy}{dx} = \frac{5x^6 - 6x^3 + 15\pi x^4 + 9x^2 + 3\pi}{(x^3 + \pi x)^2}
$$
This is the derivative of the given function.