Did you know that you can enter cos (pi/2) and get back a nice 0? The parentheses thingy is a matter you'd like to be careful with though. Because cos pi/2 is treated as (cos (pi))/2. For that matter, log, ln, e are all keywords (just like your pi) with proper arguments. What is surprising, unfortunately, is that there are no hyperbolic functions. Try with arccos, acos -- they don't work. One more of Google's strange omissions. Oddly enough, (9^9)^9 works and so does e^e^e whereas 9^9^9 doesn't! 5/5 returns 1, 1/0 doesn't work. Next, try out tan (pi/2) on your desktop calculator (if you don't know what it is). Mine says 'invalid input for function'. Google is smart, real smart. Check for yourself! Check out more Google oddities on reddit -- here.

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