Second Partial Derivative Calculator

Find fxx, fxy, and fyy for a quadratic two-variable function.

Multivariable CalculusPartial DerivativesCollege Math

Calculator

a in ax²
b in bxy
c in cy²
d in dx
e in ey
constant
Please enter valid values.

What this calculator teaches

Second partial derivatives describe curvature in the x direction, y direction, and mixed direction.

They are the building blocks of the Hessian matrix used in optimization and surface analysis.

Formula & Symbols

ConceptFormulaMeaning
Second x partialfxx = ∂²f/∂x²Curvature when y is held constant.
Mixed partialfxy = ∂²f/∂x∂yHow the x-slope changes as y changes.
Second y partialfyy = ∂²f/∂y²Curvature when x is held constant.

Step-by-Step Examples

Example 1
f=2x²+3xy+4y²+x-2y+5
  • fxx=2·2.
  • fxy=3.
  • fyy=2·4.
✓ fxx=4, fxy=3, fyy=8.

Where students use this

🎓
College mathematics
Use the tool to connect notation, formulas, and numeric answers.
🧪
Engineering analysis
Apply the result to models, systems, approximations, and design calculations.
💻
Computer science
Use matrix, vector, numerical, and optimization ideas in algorithms and data work.

Common Mistakes to Avoid

⚠️
Ignoring restrictions

Check denominator, domain, endpoint, and matrix-invertibility conditions before trusting a result.

⚠️
Rounding too early

Carry extra decimals through intermediate steps and round only the final answer.

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Mixing symbolic and numeric answers

Some topics need exact symbolic reasoning, while this calculator gives a clear numerical learning check.

Frequently Asked Questions

Is this calculator meant for students? ▾
Yes. It gives an answer and shows the main method so students can learn the reasoning instead of copying only the result.
Can I use decimals and negative numbers? ▾
Yes, when the topic allows them. Some formulas have restrictions such as positive radii, nonzero denominators, or valid intervals.
Why can textbook answers look different? ▾
Equivalent algebraic forms, different rounding, or using exact notation instead of decimals can make answers look different while meaning the same thing.

Related Math Calculators

Formula Explorer connections

Interpretation: This formula measures limiting behavior, instantaneous change, accumulation or multivariable variation. Assumption: The function must satisfy the continuity or differentiability conditions required by the method. Check domains, bounds, orientation and singularities.

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