> > Could you please help me and explain how the book > gets to the solution? > - I do not get how the velocity (v) results 2. - > > Exercise. > What functions have f (t + 1)=f (t)+ 2? > Solution. > The function increases by 2 in one time unit so the > slope (velocity) is 2; f (t) =2t +C with constant C > =f (0). > Hi Vlad, f(t) is a function of t, as its value changes as t changes. velocity is the rate of change of f with respect to t, written as df/dt In this case f(t) = 2*t + C When t=0 f(t)=C To get v, which is df/dt, differentiate with respect to t The differential of 2*t wrt t is 2, so v=2 If t increases by 1, f increases by 2 If t increases by 3, f increases by 6 Draw a graph with t on the x-axis, f on the y-axis It is a straight line, goes thru (0,C) and has a slope of +2 Saying f(t+1)=f(t)+2 is just another way of saying if t increases by 1 then f increases by 2 Hope this helps. Regards, Peter Scales.