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Question

Mathematics Question on Trigonometric Functions

If α,β,γ\alpha, \beta, \gamma are any three angles, then cosα+cosβcosγcos(α+β+γ)=\cos \, \alpha + \cos \beta - \cos \, \gamma - \cos (\alpha + \beta + \gamma) =

A

4cosα+β2cosβ+γ2cosγ+α24 \cos \frac{\alpha+\beta}{2} \cos \frac{\beta+\gamma}{2} \cos \frac{\gamma+\alpha}{2}

B

4cosα+β2sinβ+γ2sinγ+α24 \cos \frac{\alpha+\beta}{2} \sin\frac{\beta+\gamma}{2} \sin\frac{\gamma+\alpha}{2}

C

4cosα+β2sinβγ2sinγα24 \cos \frac{\alpha+\beta}{2} \sin\frac{\beta - \gamma}{2} \sin\frac{\gamma - \alpha}{2}

D

4sinα+β2cosβ+γ2cosγ+α24 \sin \frac{\alpha+\beta}{2} \cos \frac{\beta+\gamma}{2} \cos \frac{\gamma+\alpha}{2}

Answer

4cosα+β2sinβ+γ2sinγ+α24 \cos \frac{\alpha+\beta}{2} \sin\frac{\beta+\gamma}{2} \sin\frac{\gamma+\alpha}{2}

Explanation

Solution

Answer (b) 4cosα+β2sinβ+γ2sinγ+α24 \cos \frac{\alpha+\beta}{2} \sin\frac{\beta+\gamma}{2} \sin\frac{\gamma+\alpha}{2}