Question

How do I calculate the magnitude of BD? (Vectors)

Answer 1

|<a,b,c,........,z>| = sqrt(a^2+b^2+......+z^2)

Answer 2

I want to use pythagorean and I tried:

|BD}^2 = |a|^2 + |b|^2 - 2|a||b|cos(BCD)

Answer 3

but I always keep getting the wrong answer... :| when it's suppose to be

Answer 4

now its a law of cosine problem