KCET 2015 Math Solved Paper

Given that,

→

a

=

∧

i

+2

∧

j

+

∧

k

→ (1)

→

b

=

∧

i

−

∧

j

+

∧

k

→ (2)

→

c

=

∧

i

+

∧

j

−

∧

k

→ (3)
A vector in the plane of

→

a

and

→

b

can be written as,

→

r

=m

→

a

+n

→

b

So, projection on

→

c

by

→

r

is given by
⇒‌

2m−n

√3

=‌

1

√3

As use can see from Eq. (4), the ˆi component and the

⋀

k

component must be equal and

⋀

j

can be either −1 or 1.
Therefore, option (4) is correct, that is 4

∧

i

−

∧

j

+4

∧

k