AP EAMCET2008MathematicsVector Algebra
If the points with position vectors 60 i +3 j , 40 i -8 j and a i -52 j are collinear, then a is equal to
Options
- A-40
- B-20
- C20
- D40
Correct answer
A. -40
Step-by-step solution
Since, the position vectors 60 i +3 j , 40 i -8 j , and a i -52 j are collinear. | array ccc 60 & 3 & 1 40 & -8 & 1 a & -52 & 1 array |=0 aligned & 60(-8+52)-3(40-a) & +1(-2080+8 a)=0 & 2640-120+3 a-2080+8 a=0 & 440+11 a=0 a=-40 aligned