Implicit Differentiation 08D41B
1. The problem is to find the derivative $y'$ for the equation $$\frac{x}{y^3} = 1$$ using two methods: (a) solving explicitly for $y$ and then differentiating, and (b) using implicit differentiation.
2. First, solve the equation for $y$ explicitly:
$$\frac{x}{y^3} = 1 \implies y^3 = x \implies y = x^{\frac{1}{3}}$$
3. Differentiate $y = x^{\frac{1}{3}}$ with respect to $x$ using the power rule:
$$y' = \frac{1}{3} x^{-\frac{2}{3}} = \frac{1}{3x^{\frac{2}{3}}}$$
4. Now, use implicit differentiation on the original equation:
Start with:
$$\frac{x}{y^3} = 1$$
Rewrite as:
$$x = y^3$$
Differentiate both sides with respect to $x$:
$$1 = 3y^2 \frac{dy}{dx} = 3y^2 y'$$
5. Solve for $y'$:
$$y' = \frac{1}{3y^2}$$
6. Check that the two derivatives are equivalent by substituting $y = x^{\frac{1}{3}}$ into the implicit derivative:
$$y' = \frac{1}{3 (x^{\frac{1}{3}})^2} = \frac{1}{3 x^{\frac{2}{3}}}$$
This matches the explicit derivative found in step 3.
Final answer:
$$y' = \frac{1}{3x^{\frac{2}{3}}}$$