1. Tardigrade
  2. Question
  3. Mathematics
  4. If two vectors a and b are such that | a |=2,| b |=3 and a ⋅ b =4, then | a - b | is equal to

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. If two vectors $a$ and $b$ are such that $| a |=2,| b |=3$ and $a \cdot b =4$, then $| a - b |$ is equal to

Vector Algebra

Solution:

We have $|a-b|^2=(a-b) \cdot(a-b)$
$=a \cdot a-a \cdot b-b \cdot a+b \cdot b$
$=|a|^2-2(a \cdot b)+|b|^2$
$=(2)^2-2(4)+(3)^2$
Therefore $|a-b|=\sqrt{5}$