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Two vectors → → B and A have equal magnitudes. The magnitude of ( → → + B A ) is ‘n’ times the magnitude of ( → → − B A ). The angle between → → B and A is -

1. sin –1 ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ + − 1 n 1 n
2. sin –1 ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ + − 1 n 1 n 2 2
3. cos –1 ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ + − 1 n 1 n 2 2
4. cos –1 ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ + − 1 n 1 n

Correct answer: cos –1 ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ + − 1 n 1 n 2 2

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