Hi! :) The question is for r (t) =<t, 4-t2, 0>, find N(t),T(t), and B(t). First I took the derivative of r (t), and divided it by its length to calculate T(t), which is <1/sqrt(1+4t2),-2t/sqrt(1+4t2,0)>. Then I took the derivative of this using the product rule, and divided it by its length to calculate N(t), which is <-2t/sqrt(1+4t2),-1/sqrt(1+4t2),0)>. Taking the cross product of these two gives the binormalvector, which is <0,0,0>. Is this done correctly, or does anyone get a different answer? Thanks in advance! I didn't do all of the work on here, but I hope that's okay, as I have already done the work to find the answer...?