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If I have a line segment that starts at origins and is parallel to the x-axis, how do I work out the position on the X axis of x if it is rotated by say 45 degrees?

I know the degree and I know the length of the line.. so I use what formula?

Is it cos(angle) / length?

aJynks
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  • Draw a picture -- it's a right triangle. Then you're pretty much done. – Jonathan Sep 21 '12 at 04:44
  • could you explain that.. I need a way to write is in a formula? – aJynks Sep 21 '12 at 04:52
  • the hypotenuse is your line segment's length and the angle it makes with the $x$-axis is your angle. The answer will turn out to be $({\rm length})\cdot\cos({\rm angle})$. – Jonathan Sep 21 '12 at 04:53
  • so what was that stuff on the wiki http://en.wikipedia.org/wiki/Rotation_%28mathematics%29#Matrix_algebra ... Like it semaed to say "the new position of x = cos(angle) - sin(angle) * length" – aJynks Sep 21 '12 at 05:03
  • I'm not sure where you're finding the thing you're referring to. In your case, you are looking for $x'$ while $x={\rm length}$ and $y=0$. – Jonathan Sep 21 '12 at 05:16

1 Answers1

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http://en.wikipedia.org/wiki/Rotation_%28mathematics%29

This article provides the complete detail of your requisite

Bach
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