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Listed below are four wave equations describing a wave moving at a velocity, $v$ $=$ $25$ $m/s$, of which only one is possible.

Which wave equation is possible?

$y(x,t)=3.5\cos (2.09t-0.084x)$

$y(x,t)=2.5\cos (0.084t-2.09x)$

$y(x,t)=1.25\cos (3.19t-8.53x)$

$y(x,t)=7.33\cos (0.25t-1.67x)$