Turn on thread page Beta
    • Thread Starter

    I'm doing fp2 and I'm struggling in sketching polar curves I can do the simple ones okay but the spec is saying I am expected to be able to sketch like 10 different functions, how am I suppose to know what the shape will look like for different types of polar curves does the examiner expect me to know all of them?

    It's funny cause 2 days ago I was in the same position as you! What I did was watch YouTube videos (Krista King has a few short simple ones) on how they plotted it then created my own notes from that to refer back to. Having a scientific calculator helps as you can put the equation in the "table" function between the limits and it tabulates the results for you to then plot.


    To give an example of how I do it for the curve r = a(root 2 + 2cos(theta)),
    Assume a = 1. Enter the values of your axes (0, pi/2, pi and 3pi/2) for theta and see what you get. The table function is very useful for this. You plot these and any other theta values will give cos(theta) recognisable values like 1, (root 3)/2 etc. Note, 1 is equivalent to a on your axis, 2 to 2a etc.

    Then think of the shape of the cartesian (non-polar) cos graph. Between 0 and pi/2 it starts at 1 and slopes downward slowly, increasing in speed and it slopes fastest as it approaches 0. The areas where it slopes quickly means a large rotation/change in angle, and vice versa for a gradual slope. So join up your points following that principle. This is better than spending time plotting individual points as the questions typically say "sketch" and aren't worth many marks, at least in my exam board, OCR MEI. I hope this makes sense!


    There is probably a way to group them.
Submit reply
Turn on thread page Beta
Updated: October 8, 2017


students online now


Exam discussions

Find your exam discussion here

Should predicted grades be removed from the uni application process
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

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.