If the vector has magnitude

MATHEMATICS · Single correct · A Level · Mathematics · Vectors · Vectors

Problem

If the vector

\vec{r}=(\lambda)\mathbf{i}+(\lambda+2)\mathbf{j}+(2\lambda)\mathbf{k}

has magnitude

6

, determine the positive value of

\lambda

. (a) 1 (b) 2 (c)

\frac{1}{3}

(d)

\frac{-1+\sqrt{33}}{2}