Find two vectors which are perpendicular, and one of them is twice the magnitude of the other. Also their sum should be (6,8).(adsbygoogle = window.adsbygoogle || []).push({});

First of all let the coords be (x,y) and (a,b)

then the magnitude of one of them is twice the other i .e . [tex] 2 \sqrt{x^2+y^2} = \sqrt{a^2+b^2} [/tex]

also their dot product is zero

[tex] (x,y) \cdot (a,b) = 0 -> xa + yb = 0 [/tex]

also the cross product is just the magnitudes of the vectors multiplied

[tex] (x,y) \times (a,b) = 2 (x^2 + y^2) [/tex]

But somehow i cannot get the fact that they add up to 6,8 to work into this framework i have setup

Is it simpler than i think it is??

Please help!!!!! Thank you in advance!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Help me with cross product question!

**Physics Forums | Science Articles, Homework Help, Discussion**