Question

find the dot product v⋅w:
for v=i-j, w=i+j

Answer 1

\[\mathbf{v}\cdot\mathbf{w}=\langle 1,-1\rangle\cdot\langle 1,1\rangle\]\[=1(1)+-1(1)=0\]

Answer 2

do you know how i would find the angle to that?

Answer 3

plot those two vectors onto a graph.

Answer 4

ok and find the missing angle?

Answer 5

you can also use is the fact that for two vectors with magnitudes \(a\) and \(b\), with angle \(\theta\) between the two vectors, the dot product is\[\mathbf{a}\cdot\mathbf{b}=ab\cos{\theta}\]

Answer 6

so \(0=\cos{\theta}\)

Answer 7

ok thats simple

Answer 8

thanks bro