Obtain the magnitude of 2A - 3B if
`A = hati +hatJ- 2 hat k and b = 2 hat I - hat j+hat k` .

Options

A. `sqrt(90)`
B. `90`
C. `3sqrt10`
D. both option A and option C correct

Answer

D

Explanation

`2A-3B=(hati+hatj-2hatk)-3(2hatj-hatj+hatk)=-4hati+5hatj-7hatk`
` therefore` Magnitude of
`2A-3B=sqrt((-4)^(2)+(5)^(2)+(-7)^(2))`
`=sqrt(16+25+49)=sqrt(90)`