Question

if A vector=i^+2j^-3k^And Bvector=3i^-j^+2k^ then find out (a) |2A+3B| (b)|3A+2B| ​

Answer 1

Step-by-step explanation:

Any vector in the plane b and c is

r=b+λc=(i+2j+k)+λ(i+j−2k)

=(1+λ)i+(2+λ)j+(−1−2λ)k

Projection of r on a is =

∣a∣

r.a

=

4+1+1

2(1+λ)−(2+λ)−(1+2λ)

=

6

−λ−1

∴

6

−λ−1

=±

3

2

⇒−λ−1=±2⇒λ=−3,1

Hence r=−2i−j+5k and r=2i+3j−3k

Answer 2

Look at this picture.........