Consider The Equation Xy^2 + X^2 Y = 6a
Consider The Equation Xy2 X2y 6a
Consider the equation xy² − x²y = 6 and perform the following tasks: (a) Use implicit differentiation to determine dy/dx. (b) Calculate the instantaneous rate of change dy/dx at the point (2, −1). (c) Find the equation of the line tangent to the graph at the point (2, −1).
Paper For Above instruction
Understanding implicit differentiation and its applications is crucial in calculus, especially when dealing with equations where y is not explicitly isolated. The equation xy² − x²y = 6 presents such a case, requiring differentiation with respect to x while treating y as a function of x. This paper will systematically address each part of the task, providing the methodological steps and mathematical reasoning involved.
(a) Implicit Differentiation of the Equation xy² − x²y = 6
The primary goal here is to differentiate both sides of the equation with respect to x, applying the product rule and chain rule where necessary. Starting with the original equation:
xy² − x²y = 6
Differentiate term-by-term:
For the first term xy², applying the product rule, we get:
d/dx [xy²] = (dy/dx)x + y² d/dx[x] = y² + x 2y dy/dx
Similarly, for the second term −x²y:
d/dx [−x²y] = −(2x y + x² dy/dx)
Putting this together, the differentiated form becomes:
y² + 2xy dy/dx − (2xy + x² dy/dx) = 0
Expanding and grouping like terms:
y² + 2xy dy/dx − 2xy − x² dy/dx = 0
Group the dy/dx terms and constant terms:
(2xy dy/dx − x² dy/dx) + (y² − 2xy) = 0
Factor dy/dx out of the terms:
dy/dx (2xy − x²) + (y² − 2xy) = 0
Solve for dy/dx:
dy/dx = [2xy − y²] / [2xy − x²]
This expression gives the derivative dy/dx in terms of x and y.
(b) Instantaneous Rate of Change at the Point (2, −1)
Substituting x=2 and y=−1 into the expression for dy/dx:
dy/dx = [2 2 (−1) − (−1)²] / [2 2 (−1) − (2)²]
Calculate numerator:
2 2 (−1) = −4; (−1)² = 1; Numerator: −4 − 1 = −5
Calculate denominator:
2 2 (−1) = −4; (2)² = 4; Denominator: −4 − 4 = −8
Thus:
dy/dx = (−5) / (−8) = 5/8
The instantaneous rate of change dy/dx at the point (2,−1) is 5/8.
(c) Equation of the Tangent Line at (2, −1)
The tangent line at a point (x₀, y₀) has a slope m = dy/dx evaluated at that point. Using the previous part, m = 5/8.
Applying the point-slope form of a line:
y − y₀ = m (x − x₀)
Substituting x₀=2, y₀=−1, and m=5/8:
y + 1 = (5/8)(x − 2)
Expressed explicitly:
y = (5/8)(x − 2) − 1
Therefore, the equation of the tangent line is y = (5/8)(x − 2) − 1.
This comprehensive analysis demonstrates the application of implicit differentiation techniques to find derivatives, evaluate the rate of change at a specific point, and determine the tangent line equation, integral concepts in calculus analysis.
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