Vector Algebra
If $$\overrightarrow{a}$$ and $$\overrightarrow{b}$$ two collinear vectors then which of the following are incorrect
Write two different vectors having same direction
Consider $$\vec {p}=\left (\hat {i}+\hat {j}+\hat {k}\right )$$ and $$\vec {q}=\left (2\hat {i}+2\hat j+2\hat k\right )$$
The directions cosines of $$\vec {p}$$ are given by,
$$l=\dfrac {1}{\sqrt {1^2+1^2+1^2}}=\dfrac {1}{\sqrt {3}}, m=\dfrac {1}{\sqrt {1^2+1^2+1^2}}=\dfrac {1}{\sqrt {3}}$$, and $$n=\dfrac {1}{\sqrt {1^2+1^2+1^2}}=\dfrac {1}{\sqrt {3}}$$.
The direction cosines of $$\vec {q}$$ are given by
$$l=\dfrac {2}{\sqrt {2^2+2^2+2^2}}=\dfrac {2}{2\sqrt 3}=\dfrac {1}{\sqrt {3}}, m=\dfrac {2}{\sqrt {2^2+2^2+2^2}}=\dfrac {2}{2\sqrt 3}=\dfrac {1}{\sqrt {3}}$$, and $$n=\dfrac {2}{\sqrt {2^2+2^2+2^2}}=\dfrac {2}{2\sqrt 3}=\dfrac {1}{\sqrt {3}}$$.
The direction cosines of $$\vec {p}$$ and $$\vec {q}$$ are the same. Hence, the two vectors have the same direction.
If $$\overrightarrow{a}$$ and $$\overrightarrow{b}$$ two collinear vectors then which of the following are incorrect
Show that the lines $$\overleftrightarrow {PQ}$$ are $$\overleftrightarrow {RQ}$$ parallel where P,Q,R,S are the points $$(2,3,4),(4,7,8),(-1,-2,1)$$ and $$(1,2,5)$$ respectively.
Show that the vectors $$ 2\hat{i}-3\hat{j}+4\hat{k}$$ and $$ -4\hat{i}+6\hat{j}-8\hat{k}$$ are collinear.
Answer the following as true or false. (i) a⃗ and −a⃗ are collinear (ii) Two collinear vectors are always equal in magnitude. (iii) Two vectors having same magnitude are collinear. (iv) Two collinear vectors having the same magnitude are equal.
Write two different vectors having same direction