SL 5.3—Derivative of powers

Syllabus
First assessment 2021
Objective
Level
HL

The SL power rule differentiates sums of integer powers

For f(x)=axnf(x)=ax^n with integer nn, f(x)=anxn1f'(x)=anx^{n-1}. Differentiate a sum term by term and treat a constant as having derivative zero.

Negative integer powers are included where the original function is defined: d(x2)/dx=2x3d(x^{-2})/dx=-2x^{-3}. Keep coefficients, signs and domain restrictions visible before simplifying.

Example

For f(x)=4x32x1+7f(x)=4x^3-2x^{-1}+7, f(x)=12x2+2x2=12x2+2/x2f'(x)=12x^2+2x^{-2}=12x^2+2/x^2, with x0x\ne0 inherited from the original function.

This SL rule is bounded to integer exponents. Rational powers, chain, product and quotient rules belong to AHL 5.9; do not import them into this Objective.