Unless otherwise stated, all functions are functions of real numbers that return real values; although more generally, the formulae below apply wherever they are well defined — including the case of complex numbers.
The derivative of the function is In Leibniz's notation, this is written as: often abridged to Focusing on the notion of maps, and the differential being a map, this is written in a more concise way as:
If, for any real number then When this becomes the special case that if then Combining the power rule with the sum and constant multiple rules permits the computation of the derivative of any polynomial.
The derivative of for any function is: In Leibniz's notation, this is written The reciprocal rule can be derived either from the quotient rule, or from the combination of power rule and chain rule.
The quotient rule
If ' and ' are functions, then: This can be derived from the product rule and the reciprocal rule.
Generalized power rule
The elementary power rule generalizes considerably. The most general power rule is the functional power rule: for any functions ' and ', wherever both sides are well defined. Special cases
If, then when ' is any non-zero real number and ' is positive.
The reciprocal rule may be derived as the special case where.
the equation above is true for all, but the derivative for yields a complex number. the equation above is also true for all , but yields a complex number if.
Logarithmic derivatives
The logarithmic derivative is another way of stating the rule for differentiating the logarithm of a function : Logarithmic differentiation is a technique which uses logarithms and its differentiation rules to simplify certain expressions before actually applying the derivative. Logarithms can be used to remove exponents, convert products into sums, and convert division into subtraction — each of which may lead to a simplified expression for taking derivatives.
Suppose that it is required to differentiate with respect to x the function where the functions and are both continuous in both and in some region of the plane, including , and the functions and are both continuous and both have continuous derivatives for. Then for : This formula is the general form of the Leibniz integral rule and can be derived using the fundamental theorem of calculus.
Derivatives to ''n''th order
Some rules exist for computing the -th derivative of functions, where is a positive integer. These include: