The solution to this problem is to use the concept of calculus, that is, derivative. The steps of derivation are as follows: first, according to the function given in the title, find the derivative of the function; Secondly, according to the derivative, the variation and probability distribution of the function are obtained; Finally, according to the obtained variation and probability distribution, a conclusion is drawn.
The basic concept of derivative is calculus, which is a mathematical method to calculate the variation and probability distribution of functions. The basic concepts of calculus are differential, limit and integral, which can be used to calculate the variation and probability distribution of functions.