I've attached my problem set. I'm having an issue on how to write the formula to insert it into matlab. According to the problem set, dl/dt = 0.2m/s. I actually have the "solution" to the problem, though I don't understand why the answer is what it is. Basically, my instructor used the pythagorean theorem and set l[tex]^{2}[/tex] = b[tex]^{2}[/tex] + [tex]^{2}[/tex]. He then differentiated twice w.r.t time, hence dc/dt going to 0 (c is constant) and the second derivative of dl/dt going to 0 as well (dl/dt constant). The end result is d[tex]^{2}[/tex]b/dt[tex]^{2}[/tex] = (dl/dt)[tex]^{2}[/tex] - (db/dt)[tex]^{2}[/tex]. a (acceleration) is the second deriv of b evidently. Can anyone tell me the reason behind differentiating twice, also how I could possibly use that formula in matlab? Thanks.