- algorithm approximation bar binary binomial coefficients book cards carnival Carnival of Mathematics chocolate circle coins complex convolution counting decadic decimal diagrams Dirichlet factorization fibonacci fractal game games graph groups Haskell hyperbinary idempotent integers interactive irrational Ivan Niven Lagrange lehmer lucas MaBloWriMo making Mersenne moebius mu multiplication nim notation number numbers objects omega order pi prime primes primitive problem programming proof puzzle rectangles review roots sequence square strategy sum symmetry test tree triangular two-player unit unity video visualization X zero-sum
### Blogroll

### Fun

### Reference

### Categories

- algebra (46)
- arithmetic (63)
- books (29)
- calculus (7)
- challenges (52)
- combinatorics (12)
- complex numbers (6)
- computation (46)
- convergence (9)
- counting (32)
- famous numbers (48)
- fibonacci (18)
- fractals (13)
- games (34)
- geometry (56)
- golden ratio (8)
- group theory (26)
- humor (6)
- induction (7)
- infinity (19)
- iteration (24)
- links (74)
- logic (6)
- meta (41)
- modular arithmetic (24)
- number theory (72)
- open problems (11)
- paradox (1)
- pascal's triangle (8)
- pattern (87)
- people (21)
- pictures (65)
- posts without words (20)
- primes (35)
- probability (6)
- programming (17)
- proof (69)
- puzzles (11)
- recursion (16)
- review (20)
- sequences (28)
- solutions (28)
- teaching (14)
- trig (3)
- Uncategorized (6)
- video (19)

### Archives

- May 2017 (8)
- April 2017 (7)
- March 2017 (5)
- February 2017 (4)
- January 2017 (3)
- December 2016 (4)
- November 2016 (6)
- October 2016 (6)
- September 2016 (2)
- August 2016 (5)
- July 2016 (2)
- June 2016 (4)
- May 2016 (4)
- April 2016 (2)
- March 2016 (3)
- February 2016 (9)
- January 2016 (8)
- December 2015 (5)
- November 2015 (29)
- August 2015 (3)
- June 2015 (2)
- April 2015 (1)
- May 2014 (1)
- December 2013 (1)
- October 2013 (1)
- July 2013 (1)
- June 2013 (1)
- May 2013 (1)
- April 2013 (3)
- March 2013 (3)
- February 2013 (2)
- January 2013 (5)
- December 2012 (3)
- November 2012 (4)
- October 2012 (5)
- September 2012 (1)
- August 2012 (4)
- July 2012 (1)
- June 2012 (6)
- May 2012 (2)
- April 2012 (3)
- March 2012 (1)
- February 2012 (4)
- January 2012 (5)
- December 2011 (1)
- November 2011 (7)
- October 2011 (4)
- September 2011 (6)
- July 2011 (2)
- June 2011 (4)
- May 2011 (5)
- April 2011 (2)
- March 2011 (4)
- February 2011 (1)
- January 2011 (1)
- December 2010 (1)
- November 2010 (4)
- October 2010 (2)
- September 2010 (1)
- August 2010 (1)
- July 2010 (1)
- June 2010 (2)
- May 2010 (3)
- April 2010 (1)
- February 2010 (6)
- January 2010 (3)
- December 2009 (8)
- November 2009 (7)
- October 2009 (3)
- September 2009 (3)
- August 2009 (1)
- June 2009 (4)
- May 2009 (5)
- April 2009 (4)
- March 2009 (2)
- February 2009 (1)
- January 2009 (7)
- December 2008 (1)
- October 2008 (2)
- September 2008 (7)
- August 2008 (1)
- July 2008 (1)
- June 2008 (1)
- April 2008 (5)
- February 2008 (4)
- January 2008 (4)
- December 2007 (3)
- November 2007 (12)
- October 2007 (2)
- September 2007 (4)
- August 2007 (3)
- July 2007 (1)
- June 2007 (3)
- May 2007 (1)
- April 2007 (4)
- March 2007 (3)
- February 2007 (7)
- January 2007 (1)
- December 2006 (2)
- October 2006 (2)
- September 2006 (6)
- July 2006 (4)
- June 2006 (2)
- May 2006 (6)
- April 2006 (3)
- March 2006 (6)

### Meta

# Tag Archives: multiplication

## Complex multiplication: proof

In my previous post, I claimed that when multiplying two complex numbers, their lengths multiply and their angles add, like this: In particular, this means that there are always different complex numbers whose th power is equal to : they … Continue reading

## Complex multiplication and roots of unity

If played around with the question from my previous post, you probably found something like the following: That is, as the powers of we get , , and with all possible sign combinations. Of course, since , if we continue … Continue reading

## Minus times minus is plus

I’ve seen several recent posts wondering about an intuitive explanation for the fact that “a minus times a minus equal to a plus”. I understand why people would wonder about this—the way it’s often taught, it seems to be just … Continue reading

## Ways to multiply

Ξ at 360 has a couple of posts (with more to come!) listing a bunch of different algorithms for performing multiplication. Did you even know there was more than one? Would you be surprised to learn that over the years, … Continue reading

Posted in computation
Tagged algorithms, methods, multiplication