If a unit vector makes an angle with with and an acute angle θ with , then find the value of θ.

Find a vector of magnitude making an angle of with x-axis, with y-axis and an acute angle θ with z-axis.
L and M are two points with position vectors and respectively. Write the position vectors of a point N which divides the line segment LM in the ratio 2:1 externally.
Let f : R → R be defined by f(x) = 3x² – 5 and g : R → R be defined by g(x) = find gof(x) .