If #r_1=4hati+hatj-4hatk#, #r_2=-2hati+2hatj+3hatk# and #r_3=hati+3hatj-hatk#, then show that #|r_1+r_2+r_3|=7#?

1 Answer
Feb 18, 2018

See the explanation below

Explanation:

The resultant of the vectors is

#vecr_1+vecr_2+vecr_3#

#=(4hati+hatj-4hatk)+(-2hati+2hatj+3hatk)+(hati+3hatj-hatk)#

#=3hati+6hatj-2hatk#

Therefore,

The modulus is

#||vecr_1+vecr_2+vecr_3||=||3hati+6hatj-2hatk||#

#=sqrt((3)^2+(6)^2+(-2)^2#

#=sqrt(9+36+4)#

#=sqrt49#

#=7#