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maths help needed

Hi All. I need to resolve a formula for wave propagation for a civil engineering problem and its been many years since my maths A level. The formula is simply:-
v=2πf.s where v is velocity at mm/s, f is frequency in Hz and s is amplitude in mm.
Now I am expecting v to equal something in the region of 10 to 15 mm/s.
The value for 2 is obviously 2. That for pi I am taking as 3.142. I have a frequency figure of 59 Hz and an amplitude of 0.4mm. My problem is that I cannot remember the significance of the full stop between the f and the s.
Simply multiplying all 4 components together is obviously not correct, as the product is something like 10 times too great. Any 16 year old maths students out there? Regards, Carstairs
 
The dimensions look correct. v is distance/time , f is dimensionless/time, s is distance, pi is dimensionless so multiplying all looks OK. But formula looks too simple for wave propagation, although my memory won't go back 45 years to dredge it up accurately.
 
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Thanks 1sttheron for the observation and Mel again for the assistance. The full stop confused me nodrog because, while it can operate as the multiply sign, here it was evidently something else. It turns out (from Mel's link) to be the 'dot product' a function for handling vectors and I think now the formula becomes;-
v=(2 x s)+(pi x s)+(f x S) which gives a result of 25.65, much closer to my anticipated answer, but I am still not sure I have correctly applied the 'dot product'. Anyway, thanks again for your responses.
 
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