Answer:
b = 0.89
Explanation:
The given vector is, [tex]A=0.2i+bj+0.4k[/tex]
A is a unit vector
We need to find the value of b.
For a unit vector, |A| = 1
So,
[tex]0.2^2+b^2+0.4^2=1\\\\0.04+b^2+0.16=1\\\\0.2+b^2=1\\\\b^2=1-0.2\\\\b=0.89[/tex]
So, th value of b is 0.89.