Question #c42b1
1 Answer
Jun 12, 2016
We will use the following:
cos(α+β)=cos(α)cos(β)−sin(α)sin(β) cos(α−β)=cos(α)cos(β)+sin(α)sin(β) cos(45∘)=sin(45∘)=√22
With those, we have
=√22cos(θ)−√22sin(θ)
=√22cos(θ)+√22sin(θ)
Adding the two, we get
=√22cos(θ)−√22sin(θ)+√22cos(θ)+√22sin(θ)
=2(√22cos(θ))
=√2cos(θ)