The following parts are not related

Part (1) [2 marks] Determine the obtuse angle between lines

Line 1: r1=[1,4,6]+s[3,5,4]

Line 2:r2=[0,1,3]+t[2,4,2]

Part (2)[2 marks]At what point does the line r=[2,3,1]+s[2,3,1] intersect the y-axis?

Part (3)[2 marks]A line passes through the points P(7,2) and Q(1,7). Find the vector and parametric equations of this line.

Part (4)[1 mark]A plane is defined by the equation 3x4y+6z7=0. What is the normal vector of this plane.