JEE Mains Model Paper 4

We have, |k

−

a

| < |

−

a

|
|k

−

a

| < |

−

a

| = k|

−

a

| < |

−

a

| = |k| = 1 = -1 < k < 1
Also k

−

a

+

1

0

−

a

is parallel to

−

a

for all vectors of k except k =

−1

2

as for this values of k
k

−

a

+

1

2

−

a

Become null vectors and then it will not be parallel to

−

a

∴ k ∊ (-1 , 1) - {

−1

2

}