Question

three vectors p vector ,Q vector ,R vector are such that p vector = Q vector+R vector and their magnitude are in ratio 13:12:5 respectively find angle between vector p and vector R​

Answer 1

Explanation:

P=Q+R

Q=P-R

Q.Q=(P-R).(P-R)

|Ql^2=|P|^2+|R|^2-2|P||R|cosx

144=169+25-130cosx

130cosx=194-144

130cosx=50

x=cos^-1(5/13)