Question

find the magnitude of parallel vectors a and b if a is three times that of b

Answer 1

Answer:

Correct option is

B

cos

−1

(

n

2

+1

n

2

−1

)

∣A+B∣=n∣A−B∣

⟹(A

2

+B

2

+2ABcosθ)=n

2

(A

2

+B

2

−2ABcosθ)

It is given that A+B

Hence cosθ=

n

2

+1

n

2

−1

⟹θ=cos

−1

(

n

2

+1

n

2

−1

)