Fundamental Lemma of Calculus of Variations
If
with Continuous second Partial Derivatives, then 
on the Open Interval
.- Instrument Function
- Insufficient Reason Principle
- Int
- Integer
- Integer Division
- Integer Factorization
- Integer-Matrix Form
- Integer Module
- Integer Part
- Integer Relation
- Integer Sequence
- Integrable
- Integral
- Integral Brick
- Integral Calculus
- Integral Cuboid
- Integral Current
- Integral Curvature
- Integral Domain
- Integral Drawing
- Integral Equation
- Integral of Motion
- Integral Sign
- Integral Test
- Integral Transform