By definition, the dot product between two vectors is given by:
[tex] a.b = | a || b | cos (\alpha) [/tex]
We have then that for this case:
[tex] | a | = 60 [/tex]
[tex] | b | = 90 [/tex]
[tex] \alpha = \frac{3\pi}{4} [/tex]
Therefore, substituting values we have:
[tex] a.b = | 60 || 90 | cos (\frac{3\pi}{4}) [/tex]
[tex] a.b = -3818 [/tex]
Answer:
The product point of the vectors is:
[tex] a.b = -3818 [/tex]
