SOLUTION: Vectors a=(4,0,2) b=(6,-3,0)
1. Show clearly that cosθ=4/5
2. Hence,or otherwise, find the exact value of cos2θ.
1. I got Cosθ=a.b/|a||b|
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-> SOLUTION: Vectors a=(4,0,2) b=(6,-3,0)
1. Show clearly that cosθ=4/5
2. Hence,or otherwise, find the exact value of cos2θ.
1. I got Cosθ=a.b/|a||b|
Log On
1. Show clearly that cosθ=4/5
2. Hence,or otherwise, find the exact value of cos2θ.
1. I got Cosθ=a.b/|a||b|
=24/√20x√45
=24/30
=4/5
It's part 2. that I am stuck on which is to find the exact value of cos2θ.
Any help will be greatly appreciated.
Andy. Answer by robertb(5830) (Show Source):
