Given ∣a∣=5, ∣b∣=2, and a⋅b=6
Using the dot product formula a⋅b=∣a∣∣b∣cosθ:
6=5×2×cosθ
6=10cosθ
cosθ=106=0.6
Using the identity sin2θ+cos2θ=1:
sin2θ=1−cos2θ
sin2θ=1−(0.6)2
sin2θ=1−0.36
sin2θ=0.64
sinθ=0.8
Note: The angle between two vectors is always between 0° and 180°, so sinθ is positive.
Using the cross product magnitude formula ∣a×b∣=∣a∣∣b∣sinθ:
∣a×b∣=5×2×0.8
∣a×b∣=10×0.8
∣a×b∣=8
Therefore, ∣a×b∣=8