Question

For \[\vec b_1=(1,2,2)\] and \[\vec b_2=(3,2,6)\], which pair gives their magnitudes?

Options

• \[|\vec b_1|=\sqrt{5},\quad |\vec b_2|=\sqrt{13}\]

• \[|\vec b_1|=7,\quad |\vec b_2|=3\]

• \[|\vec b_1|=3,\quad |\vec b_2|=7\]

• \[|\vec b_1|=9,\quad |\vec b_2|=49\]

Answer 1

\[|\vec b_1|=\sqrt{1^2+2^2+2^2}=\sqrt9=3\]. Also, \[|\vec b_2|=\sqrt{3^2+2^2+6^2}=\sqrt{49}=7\].