Question

Hi, can someone help me with parallel vectors? I have vector PR=<-1,10>, and I want to find another vector parallell to it.

Answer 1

multiply it wid a scalar number

Answer 2

so would <-2,20> be a good answer?

Answer 3

yup !

in general, say \(\overrightarrow{PR}\) is a vector, then the vector \(k\overrightarrow{PR}\) will be parallel vector. \(k\) can be any scalar.
if k is positive, then the resulting vector will be in same direction,
if k is negative, then the resulting vector will be in opposite direction.

Answer 4

And also the dot product should equal 1 right? To show the angle between 2 vectors in 0 deg

Answer 5

oh to show the angle between them is 0, u need to show \(\cos(\theta) = \cos(0) = 1\)

Answer 6

u may use dot product formula for that

Answer 7

\(\vec{A} . \vec{B} = |\vec{A}| |\vec{B}|\cos(\theta)\)

plugin values of both vectors

Answer 8

\(<-1, 10> . <-2, 20> = \sqrt{(-1)^2 + 10^2}\sqrt{(-2)^2+20^2} \cos(\theta)\)

simplify and solve \(\cos(\theta)\)

Answer 9

Thank you! (;

Answer 10

np :) u knw how to do the left hand side right ?

Answer 11

Yes.

Answer 12

good :)