Class 12

Math

Algebra

Vector Algebra

Write the direction ratios of the vector $→a=i^+j^ −2k^$and hence calculate its direction cosines.

So, direction ratios will be $(1,1,−2)$.

Let its direction cosines are (k,k,-2k).

Then,$k_{2}+k_{2}+(−2k)_{2}=1$

$6k_{2}=1$

$k=±6 1 $

We will take $k=6 1 $ for direction cosines in the same direction of vector.

So, direction cosines will be $(6 1 ,6 1 ,−6 2 )$