for the following two vectors find the constant 'p' such that the vectors a & b are perpendicular:(adsbygoogle = window.adsbygoogle || []).push({});

a = i + 2pj +3pk

b = i - 2j + pk

the answer is: p = 1 & p = 1/3, but how is this calculated? any help would be massively appreciated

i understand that the angle between the vectors, when perpendicular would be 90 degrees and apparently the dot product should be equal to zero, however the answer would suggest otherwise????

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

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

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

# Homework Help: Find unknown constant of two vectors to make vectors perpendicular to each other?

**Physics Forums | Science Articles, Homework Help, Discussion**