Hi folks,(adsbygoogle = window.adsbygoogle || []).push({});

When you're squaring the sum of two vectors (v_1 + v_2)^2, why is it that it comes out as v_1 dot v_1 plus 2*v_1 dot v_2 plus v_2 dot v_2? Why do we use the dot product here instead of cross product? I understand that dot product is the multiplication of their parallel components, but it seems arbitrary to use dot rather than cross product in this case

**Physics Forums - The Fusion of Science and Community**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# When to us dot versus cross product

Loading...

Similar Threads - versus cross product | Date |
---|---|

I Motivation and proof behind cross products | Oct 15, 2016 |

Adjoint versus classical adjoint/any relation? | May 30, 2011 |

Bijective versus Linear | Sep 26, 2010 |

AX=B versus Ax=b | Jan 7, 2009 |

Givens rotations versus Euler angles | Aug 26, 2008 |

**Physics Forums - The Fusion of Science and Community**