According to the characteristics of each topic, 1/n(n+ 1) =1/n-1(n+1) is not a conversion method, but a1/n (n+. Expand to 1/n? .
Derivative is the local property of function. The derivative of a function at a certain point describes the rate of change of the function near that point. If the independent variables and values of the function are real numbers, then the derivative of the function at a certain point is the tangent slope of the curve represented by the function at that point.
Scaling method? Scaling means making inequality a.