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DochEvi [55]
3 years ago
13

Solve the equation on the interval [0, 2pi) 2 cos^2 (theta/2) - 3 cos theta = 0

Mathematics
1 answer:
Ksivusya [100]3 years ago
3 0
Hello : 
by idetity : 1+cos(2a) = 2cos²(a)
let : a = <span>θ/2
1+cos(2×</span>θ/2)=2cos²(θ/2)
1+cos(θ) = 2cos²(θ/2)
solve :  2 cos^2 (θ/2) - 3 cos(θ) = 0   ......(1)
(1) : 1+cos(θ)-3 cos(θ) =0
2cos(θ)  = 1 

cos(θ) = 1/2
in : [0, 2π<span>[ 
</span>( θ = π/3) or (θ = 5π/3)
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3 0
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*see photo for complete solution*

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