BeginnerTopic 29 of 104Engineering Mathematics

Derivatives of common functions

d/dx sin x = cos x, d/dx e^x = e^x, d/dx ln x = 1/x; the standard table of engineering calculus.

In depth

Standard results: (eˣ)'=eˣ, (ln x)'=1/x, (sin x)'=cos x, (cos x)'=-sin x, (tan x)'=sec²x, (aˣ)'=aˣ ln a, (arctan x)'=1/(1+x²). Memorising them speeds up analysis.

Key points

  • Chain rule extends each entry
  • Hyperbolic functions have similar rules
  • Integrals are the reverse
Example

d/dt (V e^{-t/RC}) = -(V/RC) e^{-t/RC}, the capacitor discharge rate.

Why it matters

A short table of standard derivatives covers most of the calculus needed for signals, mechanics and thermodynamics.

Where this is used

  • Differentiating an exponential decay model for a capacitor voltage.
  • Finding the rate of change of a logarithmic sensor output.
  • Differentiating sine waves to get acceleration from displacement.

Frequently asked questions

What is Derivatives of common functions?

d/dx sin x = cos x, d/dx e^x = e^x, d/dx ln x = 1/x; the standard table of engineering calculus.

Why is it important to understand derivatives of common functions?

A short table of standard derivatives covers most of the calculus needed for signals, mechanics and thermodynamics.

Why is the derivative of e to the x itself?

It is the unique function whose growth rate equals its value, which is why exponential growth and decay are so common in physical laws.

What is the derivative of a constant?

Zero, because a constant does not change with the input.

How is Derivatives of common functions used in practice?

Typical applications include differentiating an exponential decay model for a capacitor voltage, finding the rate of change of a logarithmic sensor output and differentiating sine waves to get acceleration from displacement.

What should I learn before Derivatives of common functions?

Study "Differentiation rules" first (topic 28 of 104 in Engineering Mathematics). It covers the groundwork this topic builds on.

What are the key points of Derivatives of common functions?

Chain rule extends each entry. Hyperbolic functions have similar rules. Integrals are the reverse.

Can you give an example of Derivatives of common functions?

d/dt (V e^{-t/RC}) = -(V/RC) e^{-t/RC}, the capacitor discharge rate.

What comes after Derivatives of common functions?

The next topic is "Applications of derivatives", which builds directly on this one.

How difficult is Derivatives of common functions?

It is classed as Beginner in Engineering Mathematics (topic 29 of 104). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.

Learning path

Want to practise? Open the interactive course for quick checks, quizzes, simulations and progress tracking.

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