اريد تعريف رياضي دقيق لـ(smooth functions)

saraabdo

New Member
definition smooth functions


لوا موجود هذا التعريف في اي كتاب ارجوامنكم المساعدة (blush)
 


salmualikom​

Indeed, the word smooth is commonly used in the theory of analytic geometry in calculus of several variables​

the smoothness of a curve or surface is just curve (surface) with continuously differentiable parametraization functions, i.e., there is no singular point on the graph of the curve (surface). Usually, a function f is smooth function in convention is just a continuous function (the function which has not singular points ) i think we have now a clear definition as you request

with my wishes
 
بارك الله فيك أخي العُمري بالفعل إجابة صحيحة
أي بمعنى آخر أن هذه الدالة تملك مشتقات مستمرة في فترة معينة.

يمكن إيضاُ الإطلاع على هذا التعريف من موقع
http://mathworld.wolfram.com
على هذا الرابط
http://mathworld.wolfram.com/SmoothFunction.html

Smooth Function
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A smooth function is a function that has continuous derivatives up to some desired order over some domain. A function can therefore be said to be smooth over a restricted interval such as
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or
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. The number of continuous derivatives necessary for a function to be considered smooth depends on the problem at hand, and may vary from two to infinity. A function for which all orders of derivatives are continuous is called a C-infty-function.​


وهذا رابط آخر لتعريف أكثر تفصيلاً

http://planetmath.org/encyclopedia/ContinuouslyDifferentiable.html
 


salmualikom​

Indeed, the word smooth is commonly used in the theory of analytic geometry in calculus of several variables​

the smoothness of a curve or surface is just curve (surface) with continuously differentiable parametraization functions, i.e., there is no singular point on the graph of the curve (surface). Usually, a function f is smooth function in convention is just a continuous function (the function which has not singular points ) i think we have now a clear definition as you request

with my wishes


also Functions that have derivatives of all orders are called
smooth FUNCTION
 


Yes mr. Dedoda you are right but in this case we call the function
C^(infinty) function i.e., all of it's derivatives are exists

An example of C^ infinty function is the famous and imporatant function defined by

f(t) = e^(-1/t) if t > 0 and f(t) = 0, if t <= 0

we notice that the n-derivatives at 0 is 0. This function very important in Measure theory and in Fourier Analysis
 
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