use implicit differentiation to find an equation of the tangent line to the curve at the given point…

use implicit differentiation to find an equation of the tangent line to the curve at the given point. x^{2/3}+y^{2/3}=4, (-3\\sqrt{3},1) (astroid)

use implicit differentiation to find an equation of the tangent line to the curve at the given point. x^{2/3}+y^{2/3}=4, (-3\\sqrt{3},1) (astroid)

Answer

Explanation:

Step1: Differentiate both sides

Differentiate $x^{2/3}+y^{2/3}=4$ with respect to $x$. Using the power - rule and chain - rule, we have $\frac{2}{3}x^{-1/3}+\frac{2}{3}y^{-1/3}y' = 0$.

Step2: Solve for $y'$

First, factor out $\frac{2}{3}$: $\frac{2}{3}(x^{-1/3}+y^{-1/3}y') = 0$. Then, solve for $y'$: [ \begin{align*} x^{-1/3}+y^{-1/3}y'&=0\ y^{-1/3}y'&=-x^{-1/3}\ y'&=-\left(\frac{y}{x}\right)^{1/3} \end{align*} ]

Step3: Find the slope at the given point

Substitute $x = - 3\sqrt{3}$ and $y = 1$ into $y'$: [ \begin{align*} y'&=-\left(\frac{1}{-3\sqrt{3}}\right)^{1/3}\ &=\left(\frac{1}{3\sqrt{3}}\right)^{1/3} \end{align*} ] The slope of the tangent line $m = \sqrt{3}$.

Step4: Use the point - slope form

The point - slope form of a line is $y - y_1=m(x - x_1)$. Here, $x_1=-3\sqrt{3}$, $y_1 = 1$ and $m=\sqrt{3}$. [ \begin{align*} y - 1&=\sqrt{3}(x + 3\sqrt{3})\ y - 1&=\sqrt{3}x+9\ y&=\sqrt{3}x + 10 \end{align*} ]

Answer:

$y=\sqrt{3}x + 10$