- Let be continuous on the interval, then there exists differentiable function on, such that for any in,. In words, the continuous functions must have antiderivatives.
- The unknown displacement field is approximated by discontinuous, piecewisely differentiable functions.
- partially differentiable function
- n - time differentiable function
- piecewise continuous differentiable function
- The approximation of differentiable functions by a kind of interpolatory rational functions is discussed,and the corresponding order of approximation is obtained.