Multivariable Calculus

How to solve

f_xx differentiates in x twice while y rides along as a constant (and symmetrically for f_yy).

Steps

  1. Differentiate in the chosen variable, treating the other as constant.
  2. Differentiate the result in the same variable again.
  3. Keep the other variable's powers untouched.

Example

f(x, y) = 2x³y². Find f_xx.

  1. f_x = 6x²y².
  2. f_xx = 12xy².

Answer: 12xy^2

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