Show that the curves r1(t) = t sin ti + t cos tj + tk , /2 t /2 and r2(s) = si

Show that the curves r1(t) = t sin ti + t cos tj + tk , −π/2 ≤ t ≤ π/2 and

r2(s) = si + sin sk, −π/2 ≤s ≤ π/2 intersect only at the origin and find the angle with which they intersect.