Math Problem Statement

Use implicit differentiation to find an equation of the tangent line to the curve x^(2/3) + y^(2/3) = 4 at the point (-3√3, 1).

Solution

To solve this problem, we need to use implicit differentiation to find the equation of the tangent line to the curve defined by the equation:

x2/3+y2/3=4x^{2/3} + y^{2/3} = 4

at the point (33,1)\left(-3\sqrt{3}, 1\right).

Step-by-step solution:

  1. Differentiate the equation implicitly with respect to xx:

    We start with: x2/3+y2/3=4x^{2/3} + y^{2/3} = 4

    Differentiating both sides with respect to xx implicitly, we get: ddx(x2/3)+ddx(y2/3)=ddx(4)\frac{d}{dx}(x^{2/3}) + \frac{d}{dx}(y^{2/3}) = \frac{d}{dx}(4) Since 4 is a constant, its derivative is 0. Now let's handle the two terms on the left-hand side.

    • For ddx(x2/3)\frac{d}{dx}(x^{2/3}), use the power rule: ddx(x2/3)=23x1/3\frac{d}{dx}(x^{2/3}) = \frac{2}{3}x^{-1/3}

    • For ddx(y2/3)\frac{d}{dx}(y^{2/3}), we must use the chain rule since yy is a function of xx: ddx(y2/3)=23y1/3dydx\frac{d}{dx}(y^{2/3}) = \frac{2}{3}y^{-1/3} \cdot \frac{dy}{dx}

    Therefore, the differentiated equation becomes: 23x1/3+23y1/3dydx=0\frac{2}{3}x^{-1/3} + \frac{2}{3}y^{-1/3} \cdot \frac{dy}{dx} = 0

  2. Solve for dydx\frac{dy}{dx}:

    Rearranging to isolate dydx\frac{dy}{dx}, we get: 23y1/3dydx=23x1/3\frac{2}{3}y^{-1/3} \cdot \frac{dy}{dx} = -\frac{2}{3}x^{-1/3}

    Simplifying: y1/3dydx=x1/3y^{-1/3} \cdot \frac{dy}{dx} = -x^{-1/3}

    Solving for dydx\frac{dy}{dx}: dydx=x1/3y1/3=(yx)1/3\frac{dy}{dx} = -\frac{x^{-1/3}}{y^{-1/3}} = -\left(\frac{y}{x}\right)^{1/3}

  3. Substitute the point (33,1)\left(-3\sqrt{3}, 1\right) into the derivative:

    At the point (33,1)\left(-3\sqrt{3}, 1\right), substitute x=33x = -3\sqrt{3} and y=1y = 1:

    dydx=(133)1/3\frac{dy}{dx} = -\left(\frac{1}{-3\sqrt{3}}\right)^{1/3}

    Simplifying: dydx=(133)1/3\frac{dy}{dx} = -\left(-\frac{1}{3\sqrt{3}}\right)^{1/3}

    Note: The cube root of a negative number will result in a negative value. Simplifying further, you can compute the cube root of the fraction for the final slope.

  4. Use point-slope form to write the equation of the tangent line:

    The equation of a line is given by: yy1=m(xx1)y - y_1 = m(x - x_1) where mm is the slope and (x1,y1)(x_1, y_1) is the given point (33,1)(-3\sqrt{3}, 1).

Would you like further clarification or numerical simplification?

Here are 5 relative questions to deepen your understanding:

  1. How do you differentiate a function using implicit differentiation?
  2. What is the geometrical interpretation of a tangent line at a point on a curve?
  3. How does the chain rule work when differentiating implicitly with respect to xx?
  4. What are the challenges when working with cube roots in calculus?
  5. How can you check if a point lies on a given curve?

Tip: Always remember to simplify the derivative before substituting in the coordinates for easier calculations!

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Math Problem Analysis

Mathematical Concepts

Implicit Differentiation
Calculus
Tangent Line
Astroid Curve

Formulas

Implicit differentiation: d/dx[f(y)] = f'(y) * dy/dx
Equation of a line: y - y1 = m(x - x1)

Theorems

Chain Rule

Suitable Grade Level

College Level (Calculus I or II)