An odd/interesting question - I have the answer, please provide me with a problem!

[EMC199]

This is a strange request, but I'm actually hosting a 40th birthday party for a dear friend who is an excellent mathematician. I want a logo for koozies which will show an advanced calculus 'problem' where the answer must be 40

I know this sounds strange but I feel like I'm coming to the right place. I just want it to look more interesting than 5+5+20+10. I haven't touched this sort of math in years.

Thanks in advance!

 

[Harry_the_cat]

How about:

\(\displaystyle \int_{0}^{4\pi}5 sin(\frac{x}{4}) dx\)

 

[EMC199]

If that works that looks exactly like the type of problem I want! Thank you!

 

[Harry_the_cat]

It does equal 40. Maybe someone else can confirm that is correct please.