Topic: Calculate the coordinates of the point

[Hugo]

Yes for rectangles, lines and poly is with me.

Then I understand something wrong? 
For X-Ref it is unfortunately not?   


Ja für Rechtecke, Linien und Poly geht es bei mir.

Dann verstehe ich was falsch ?
Für X-Ref geht es leider nicht ?

[andy_lee]

The result only rectangle is right ! because the angle is 90
you can draw 2 line . the angle is not 90. test again

[Hugo]

Hier

[andy_lee]

Hier

The angle is still 90

[Hugo]

OK now I understand.
This is not true.   

[It's Alive!]

If you consider a vector has a distance and a direction, the direcrion can be expressed by an X distance and a Y distance,
and the hypotenuse of the triangle formed is the vector distance.

A unit vector has the triangle hypotenuse reduced to one unit with the X and Y distances modified accordingly.

This may help :
https://www.khanacademy.org/math/precalculus/vectors-precalc/unit-vectors/v/unit-vector-intro

unit vectors have little hats

[kdub_nz]

Yep ... a party hat.


but just to show they are not all frivolous ...

Consider a unit vector with a direction of 30 degrees.

cos(30) is 0.8660 which is the x offset
sin(30) is 0.50 which is the Y offset.

similarly cos(45) and sin(45) are both 0,7071  which is the the x an Y offset from the startpoint.

//------------------

My old math master used to say something like " the universe is made up of circles and triangles"
... I've since come to understand that he wasn't really joking.

[andy_lee]

Still can't understand. my math is so bad.
Math master and Lisp master .please give a fish.
@Lee Mac @ribarm @roy_043  ....

[kdub_nz]

I can't understand No.3. what is unit vector?

You're welcome.

... my math is so bad.

Well, do something about it.


I'm outa here.

[andy_lee]

This I do:
https://www.theswamp.org/index.php?topic=52652.msg575395#msg575395

I want use Lee's method. but I can't understand.

[It's Alive!]

Yep ... a party hat.

Joking aside, thanks for the link