Math Problem Statement

if x^2-xy+y^2= 3 find y prime and y double prime

Solution

To find yy' (the first derivative of yy with respect to xx) and yy'' (the second derivative), we start from the implicit equation:

x2xy+y2=3x^2 - xy + y^2 = 3

Step 1: Differentiate Implicitly

Differentiating both sides with respect to xx:

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

This gives us:

2x(y+xdydx)+2ydydx=02x - (y + x\frac{dy}{dx}) + 2y\frac{dy}{dx} = 0

Step 2: Rearrange to Solve for yy'

Rearranging the equation:

2xy=xdydx2ydydx2x - y = x\frac{dy}{dx} - 2y\frac{dy}{dx}

2xy=(x2y)dydx2x - y = (x - 2y)\frac{dy}{dx}

Now, solve for dydx\frac{dy}{dx}:

dydx=2xyx2y\frac{dy}{dx} = \frac{2x - y}{x - 2y}

Step 3: Find yy''

Now we need to differentiate yy' to find yy''. Using the quotient rule:

y=(x2y)ddx(2xy)(2xy)ddx(x2y)(x2y)2y'' = \frac{(x - 2y)\frac{d}{dx}(2x - y) - (2x - y)\frac{d}{dx}(x - 2y)}{(x - 2y)^2}

Calculating ddx(2xy)\frac{d}{dx}(2x - y) and ddx(x2y)\frac{d}{dx}(x - 2y):

ddx(2xy)=2dydx\frac{d}{dx}(2x - y) = 2 - \frac{dy}{dx}

ddx(x2y)=12dydx\frac{d}{dx}(x - 2y) = 1 - 2\frac{dy}{dx}

Substituting these back into the equation for yy'':

y=(x2y)(2dydx)(2xy)(12dydx)(x2y)2y'' = \frac{(x - 2y)(2 - \frac{dy}{dx}) - (2x - y)(1 - 2\frac{dy}{dx})}{(x - 2y)^2}

Now substitute dydx=2xyx2y\frac{dy}{dx} = \frac{2x - y}{x - 2y} into the expression for yy''.

Final Expressions

Thus, we have:

  1. y=2xyx2yy' = \frac{2x - y}{x - 2y}
  2. yy'' can be expressed in terms of xx and yy using the values found.

Summary

To summarize, the derivatives are:

  • First derivative: y=2xyx2yy' = \frac{2x - y}{x - 2y}
  • Second derivative: Substitute yy' into the derived expression to find yy''.

If you need further simplification for yy'' or have questions about any specific steps, feel free to ask!

Additional Questions

  1. What are the specific values of xx and yy for which you want to find yy' and yy''?
  2. Would you like to see a graphical representation of the function?
  3. Are you interested in finding the critical points of the function?
  4. Do you need examples of similar implicit differentiation problems?
  5. Would you like to explore applications of these derivatives in real-world scenarios?

Tip: Always check if the function is defined and differentiable in the region you're investigating to ensure the derivatives are valid.

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Math Problem Analysis

Mathematical Concepts

Implicit Differentiation
First Derivative
Second Derivative
Quotient Rule

Formulas

Implicit differentiation of x^2 - xy + y^2 = 3
Quotient Rule: (f/g)' = (g f' - f g') / g^2
First derivative of y: y' = (2x - y) / (x - 2y)
Second derivative formula involving y' substitution

Theorems

Implicit Differentiation Theorem

Suitable Grade Level

Grades 11-12