Calculus I · Unit 2A · review

Core Differentiation Rules Review

Core Rules Review

Summary
(c)=0,(xn)=nxn1,(c)'=0, \qquad (x^n)'=nx^{n-1},(af+bg)=af+bg,(af+bg)'=af'+bg',(fg)=fg+fg,(fg)=fgfgg2.(fg)'=f'g+fg', \qquad \left(\frac fg\right)'=\frac{f'g-fg'}{g^2}.

Rewrite radicals and reciprocals as powers. Simplify before using a more complicated rule.

Exercise

Differentiate 7x83x1/2+5x47x^8-3x^{1/2}+5x^{-4}.

Exercise

Differentiate (x3+2x)(x21)(x^3+2x)(x^2-1).

Exercise

Differentiate (x2+4)/(x1)(x^2+4)/(x-1).

Exercise

Find the tangent line to y=x42x2y=x^4-2x^2 at x=1x=1.

Exercise

Find all inputs where the tangent to y=x33xy=x^3-3x is horizontal.

Exercise

Differentiate x2/(x3+1)x^2/(x^3+1) and state its domain.

Exercise

A square has side s(t)=t2+1s(t)=t^2+1. Find the rate of change of its area at t=2t=2.

Exercise

Identify and repair the error: ddx[(x2+1)(x31)]=2x(3x2)\frac{d}{dx}[(x^2+1)(x^3-1)]=2x(3x^2).

After the explanation

Use the section idea

Reading lens

Every rule is a compressed limit calculation; choose the structure before doing algebra.

Mental model

Sums contribute independently, products have two changing contributions, and quotients must account for a changing denominator.

Decision

Name the outermost algebraic structure, then apply the smallest rule set that preserves it.

Common trap

Applying a familiar rule to the wrong outer structure or simplifying after a differentiation error.

Check yourself

Can you justify the primary rule before writing the first derivative symbol?

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