# What this graph called and what is its equation?

I am not a mathematician and the last time I used a formula complexer than sin(x) was during my university time about 10 years ago.

Recently I saw an interesting graph but I couldn't find its formula or even its name.

here is an almost representation of the graph.

every time the graph descends, it descends to the top of last peak (in y value).

I like to know

• Is this graph has a name?
• What is its equation?
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$\sin x + x$ would be close. –  Alex Becker Apr 16 '13 at 2:18
@AlexBecker, Thanks for the answer, it is close, but it does not descend to top top of last peak here it is –  BobSort Apr 16 '13 at 2:21
I believe this does the trick: $$f(x) = \frac{2}{3 \pi} x + \cos{x}$$