Turn on thread page Beta

Fourier Coefficients by Inspection... HELP!! watch

    • Thread Starter

    I need help on the following questions. I have absolutely no idea how to do this, from working out the period to finding the Fourier coefficient.

    For each question I need to state the period and by just looking at the function, work out its Fourier coefficients.
    1) f(x) = 1 + cos(2pix) + sin(4pix)

    2) f(x) = 1 + cos^2(2pix) - cos(4pix). Hint: use 2cos^2(x) = 1 + cos(2x)

    If anyone can help it would be much appreciated.

    The easiest way to find the period would be to graph the functions and look at how often they repeat. If you need to show it formally, use the fact that f(x+k) = f(x) for all x if f has period k, so set up and solve f(x+k)=f(x) (I havent tried it, it looks like it would fall out easily with the double angle formulae).
    • Thread Starter

    Any ideas on how to get the Fourier coefficient?
Submit reply
Turn on thread page Beta
Updated: March 11, 2008

University open days

  • University of Lincoln
    Brayford Campus Undergraduate
    Wed, 12 Dec '18
  • Bournemouth University
    Midwifery Open Day at Portsmouth Campus Undergraduate
    Wed, 12 Dec '18
  • Buckinghamshire New University
    All undergraduate Undergraduate
    Wed, 12 Dec '18
Do you like exams?
Useful resources

Make your revision easier


Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here


How to use LaTex

Writing equations the easy way


Best calculators for A level Maths

Tips on which model to get

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.