Find the unit tangent vector T and the principal unit normal vector N. r(t) = (ln(cos t) + 1)i + 3j + (7 + t )k, -?/2 < t < ?/2

Question

A. T = (sin t)i  + (cos t)k; N = (cos t)i  - (sin t)k
B. T = (-sin t)i  + (cos t)k; N = (-cos t)i  + (sin t)k
C. T = (sin t)i  - (cos t)k; N = (cos t)i  - (sin t)k;
D. T = (-sin t)i  + (cos t)k; N = (-cos t)i  - (sin t)k

Answer 1

Answer: D