4. Given the vector valued function F = -zi+ xj − yk, find the scalar line integral of F along the space curve - r(t) = sin ti cos tj + e¹k between the points on the curve corresponding to t = 0 and t = π/2. Answer: Integrate F.dr between the limits t = 0 and t=л/2 to obtain л/4 5. Let F be the vector-valued function F = -xi + yj + zk. Show that the line integrals of F along the helix r(t) = sin ti + costj + tk between the points on the he- lix corresponding to t = 0 and t = 2л and along the straight line path joining the points r(0) to r(2л) are the same. Answer: 2π2