Question

Modulus of the vector 4i+3j-2k is​

Answer 1

We have vector

$\longmapsto\tt{a = 4i + 3j + 2k 2}$

vector

$\longmapsto\tt{a = 8i + 6j + 4k}$

and vector

$\longmapsto\tt{ b = 3i + 2k = 3i + 0j + 2k }$

∴ vector

$\longmapsto\tt{|b x 2a| = |(i,j,k),(3,0,2),(8,6,4)}$

$\longmapsto\tt{ i(0 - 12) - j(12 - 16) + k(18 - 0) }$

$\longmapsto\tt{-12i + 4j + 18k }$

∴ vector

$\longmapsto\tt{|b x 2a|= √(122 + 42 + 182) }$

$\longmapsto\tt{= √484 = 2√121 }$

$\longmapsto\tt{= 22}$