3'8 Differentials and Marginal Analysis

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3.8 Differentials and Marginal Analysis
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Differentials

• Let yf(x) represent a differentiable function
• dx, the differential of x, is any real number
• The differential of y is
• dyf ?(x)dx

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Approximations

• ?yf(x ?x)-f(x)
• ?y ? dy

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Marginal Analysis
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Differential Forms of Differentiation
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Error Propagation

• Relative errordy/y
• Percentage error(dy/y)x100