sketch the curve and find its arc length:
r(t)=(cos t, sin t, 6t), 0≤ t ≤ 2π
You have posted something like 6 or 7 problems with no indication that you have made any attempt yourself. Many of them involve very basic integration rules from Calc I but "arc length" is typically a Calc III topic. Here, the first thing you should have observed is that $\displaystyle x^2+y^2= cos^2(t)+ sin^2(t)= 1$ so the projection of the curve onto the xy plane is a circle. What does z do while x and y are "circling"?