The displacement of a particle is given by the equation v=20t +8t^2 .calculate the instantaneous velocity after 2seconds ,,show working

I'll need to be very careful with this one, and assume that
you know precisely what you're talking about.

It's a bit confusing at first, because you've chosen to use 'v'
to represent displacement.  But if you like 'v', then so be it.

OK.  So the displacement at any time 't' is  20t + 8t².

The magnitude of velocity = (displacement) / (time)

                    =  20 + 8t .

And of course, the direction of velocity is going to be
the direction of the displacement at time 't'.

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