The left panel computes $-r$, the right computes $-f$.
More from Chalkdust
Tennis maths: how long should a deuce point last?
Using Markov chains to calculate some interesting tennis stats!
A brief history of gravitational waves
The discovery of gravitational waves offers a new way of looking at the universe. Who knows what we will discover?
In conversation with Ian Stewart
We speak to one of Britain's most successful popularisers of maths
New largest prime number discovered!
Amaze your friends with our top facts about the new largest known prime number
What’s your favourite function? Part II
We have received loads of feedback from people telling us their favourite function
Weekend at MathsJam
Chalkdust visits popular maths' biggest conference