KCET2021MathematicsVector Algebra
If a b =0 and a + b makes an angle 60^ with a, then
Options
- A| a |=2| b |
- B2| a |=| b |
- C| a |= 3 | b |
- D3 | a |=| b |
Correct answer
D. 3 | a |=| b |
Step-by-step solution
Given, a b =0 and ( a + b ) makes 60^ angle with a. 60^ = ( a + b ) a | a + b || a | 1 2 = | a |²+ a b | a + b || a | | a + b |=2| a | | a + b |²=4| a |² ( a + b )( a + b )=4| a |² | a |²+| b |²+2 a b =4| a |² b ²=3| a |² | b |= 3 | a |