Manipal MET2018MathematicsThree Dimensional Geometry
If a , b , c are the position vectors of A, B, C respectively such that 3 a +4 b -7 c = 0 , then C divides A B in the ratio
Options
- A4:3
- B4;7
- C3:7
- D3:4
Correct answer
A. 4:3
Step-by-step solution
Let C divides A B in the ratio m: 1 . Then c = m b + a m+1 array lr & m c + c =m b + a & a +m b -m c - c = 0 & a +m b +(-m-1) c = 0 ...(i) array Given, array ll Given, & 3 a+4 b-7 c=0 & a+ 4 3 b- 7 3 c=0...(ii) array On comparing Eqs. (i) and (ii), we get m= 4 3 Required ratio is 4: 3