Math Problem Statement

Find y'' by implicit differentiation 5x^2+y^2=3

Solution

To find yy'' by implicit differentiation for the equation:

5x2+y2=35x^2 + y^2 = 3

we'll follow these steps:

Step 1: Differentiate both sides with respect to xx.

Since we have an equation involving xx and yy, we need to apply implicit differentiation:

ddx(5x2+y2)=ddx(3)\frac{d}{dx}(5x^2 + y^2) = \frac{d}{dx}(3)

Differentiating each term:

  1. For 5x25x^2: ddx(5x2)=10x\frac{d}{dx}(5x^2) = 10x
  2. For y2y^2: ddx(y2)=2ydydx=2yy\frac{d}{dx}(y^2) = 2y \cdot \frac{dy}{dx} = 2y \cdot y' (using the chain rule)
  3. For the constant 3: ddx(3)=0\frac{d}{dx}(3) = 0

Putting it all together:

10x+2yy=010x + 2y \cdot y' = 0

Step 2: Solve for yy'.

Rearrange the equation to isolate yy':

2yy=10x2y \cdot y' = -10x

y=10x2y=5xyy' = \frac{-10x}{2y} = \frac{-5x}{y}

Step 3: Differentiate yy' again to find yy''.

Now, we differentiate y=5xyy' = \frac{-5x}{y} with respect to xx to get yy'':

y=ddx(5xy)y'' = \frac{d}{dx}\left(\frac{-5x}{y}\right)

Using the quotient rule (uv)=uvuvv2\left(\frac{u}{v}\right)' = \frac{u'v - uv'}{v^2}, where u=5xu = -5x and v=yv = y:

  1. u=5u' = -5
  2. v=y=5xyv' = y' = \frac{-5x}{y}

Substitute into the quotient rule:

y=(5)y(5x)(5xy)y2y'' = \frac{(-5)y - (-5x)\left(\frac{-5x}{y}\right)}{y^2}

Simplify each term in the numerator:

y=5y+25x2yy2y'' = \frac{-5y + \frac{25x^2}{y}}{y^2}

Combine terms over a common denominator yy:

y=5y2+25x2y3y'' = \frac{-5y^2 + 25x^2}{y^3}

Final Answer:

y=25x25y2y3y'' = \frac{25x^2 - 5y^2}{y^3}

Let me know if you'd like more details, or if you have questions!


Here are some related questions:

  1. How do you apply implicit differentiation to find higher-order derivatives?
  2. How does the chain rule help in implicit differentiation?
  3. What are other methods to solve for second derivatives of implicit functions?
  4. Why is it necessary to use the quotient rule when differentiating y=5xyy' = \frac{-5x}{y}?
  5. Can you verify the solution by differentiating y=5xyy' = \frac{-5x}{y} step-by-step?

Tip: Remember, implicit differentiation treats yy as a function of xx, allowing derivatives with respect to xx on both sides of an equation.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Implicit Differentiation
Higher-Order Derivatives
Chain Rule
Quotient Rule

Formulas

Implicit differentiation of y with respect to x using the chain rule: d/dx(f(y)) = f'(y) * dy/dx
Quotient rule: (u/v)' = (u'v - uv')/v^2

Theorems

Implicit Differentiation Theorem
Chain Rule
Quotient Rule

Suitable Grade Level

Grades 10-12