Multiplying Polar Coordinates

Algebra Level 1

What do we obtain when we multiply the polar coordinates:

( r 1 , θ 1 ) × ( r 2 , θ 2 ) ? ( r_1 , \theta _1 ) \times ( r_2 , \theta _2 ) ?

( r 1 × r 2 , θ 1 × θ 2 ) ( r_1 \times r_2 , \theta_1 \times \theta _2 ) ( r 1 + r 2 , θ 1 × θ 2 ) ( r_1 + r_2 , \theta_1 \times \theta _2 ) ( r 1 + r 2 , θ 1 + θ 2 ) ( r_1 + r_2 , \theta_1 + \theta _2 ) ( r 1 × r 2 , θ 1 + θ 2 ) ( r_1 \times r_2 , \theta_1 + \theta _2 )

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Michael Mendrin
Oct 5, 2015

This is really the product of complex numbers in polar form, which returns "another complex number" also in polar form.

When we multiply two complex numbers their absolute values (moduli) get multiplied and their arguments are added. Therefore ( r 1 , θ 1 ) × ( r 2 , θ 2 ) = ( r 1 × r 2 , θ 1 + θ 2 ) . ( r_1 , \theta _1 ) \times ( r_2 , \theta _2 ) = ( r_1 \times r_2 , \theta_1 + \theta _2 ) .


A vector dot product yields a scalar, while a vector cross product yields a vector which is normal to the original two.

It's interesting how complex numbers differs from vectors in that way, even though complex numbers are often treated as if they were vectors.

What does it mean, exactly, to "multiply polar coordinates", if not talking about a product of complex numbers? This one has got me wondering about other possible spaces where this can make sense.

Yeah I was wondering if we still treated them like vectors or if they had their own outer product?

Jerry McKenzie - 4 years, 3 months ago

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...