Question

Find A dot B if |A| =2 , |B| =5 and |A×B| =8

Answer 1

Answer:

|A||B|sinΦ=8

sinΦ=8/10

sinΦ=4/5

Φ=53°

A.B = |A||B|cosΦ

= 2 x 5 x cos53°

= 10 x 3/5

= 6