Question

For the curvature of r(t)=(-4sint)i+(-4sint)j+(3cost)k, I used the equation k=|T'(t)/r'(t)| but I'm not getting the right answer

Answer 1

Calculare r'(t) then r''(t). Then r' x r'' . After that I think you can write
k = ||r' x r''|| / ||r'||^3
I hope this help but you have to check.
I am not very sure.