Question

If ( A+B)=(A)(B), then angle between A and B is. a)90 degree b)120 degree c) 0 degree d) 60 degree​

Answer 1

Answer:

we know, |A - B| = √{|A|² + |B|² - 2|A||B|cos}

where  is angel between A and B.

given, |A - B| = |A| - |B|

so, √{|A|² + |B|² - 2|A||B|cos} = |A| - |B|

squaring both sides,

|A|² + |B|² - 2|A||B|cos = |A|² + |B|² - 2|A||B|

or, -2|A||B|cos = -2|A||B|

or, cos = 1 = cos0°

or,

hence, option (B) is correct.

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Answer 2

I hope this will help you to understand the problem