Vectors in polar coordinates
11-18-2015, 09:32 AM
Post: #1
 retoa Member Posts: 168 Joined: Jan 2015
Vectors in polar coordinates
Hello !

Is there a way to work with vectors in polar coordinates (respectively spherical or cylindrical for 3D) like you do with complex numbers?

In 2D you can write the vectors as polar complex numbers for sums, but you can not do dot multiplication between complex numbers, nor cross multiplication as you need a third dimension.

With my 48sx I could do it, is it possible on the prime too, or do I have to convert all vectors in rectangular and then reconvert the result in polar after calculation?
11-18-2015, 03:38 PM
Post: #2
 Tim Wessman Senior Member Posts: 2,281 Joined: Dec 2013
RE: Vectors in polar coordinates
It is not currently possible at this time to work that way...

Yeah, I'm not happy about it either and really hope to be able to resolve it at some point before too much longer.

Right now though you can work directly in 2D using complex numbers. For example, turn on the complex (x,y) form in page 1 of the home settings. Now type (x,y) just like you did with the 48sx. Pressing the angle key will toggle the selected history item to rectangular/polar. You can also enter directly by doing (d,<angle>num). Note that whether a complex item is in rectangular or polar is *part* of the complex number itself. So they stay in that form instead of all switching back and forth based on a display setting.

TW

Although I work for HP, the views and opinions I post here are my own.
11-19-2015, 08:35 AM
Post: #3
 retoa Member Posts: 168 Joined: Jan 2015
RE: Vectors in polar coordinates
Yes, I already use this solution when I only have to do vector addition (same problem on the 35s by the way) but this is the only thing you can do.
You can not do "dot" nor "cross" product, this does not exist for complex numbers.
Matrix multiplication (e.g. with a rotation matrix) will also not give the same result with complex numbers as with vectors (obviously).
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