If cos-cos-a- sin-sin- b and -2- then cos 3-cos- is equal to-

The correct option is C a^2+b^2 3 cos 3θcosθ = 4cos ^2θ #10; 3 #10; = 2cos 2θ 1 #10; = 2cos (α β) 1 .........(1) #10;Now ...

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Product of Trigonometric Ratios in Terms of Their Sum

If cosα+cos...

Question

If $cos α + cos β = a, sin α + sin β = b$ and $α - β = 2 θ$ , then $\frac{cos 3 θ}{cos θ}$ is equal to:

a^{2} + b^{2} - 2

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a^{2} + b^{2} - 3

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3 - a^{2} - b^{2}

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\frac{a^{2} + b^{2}}{4}

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s i n α + s i n β = a

c o s α + c o s β = b,

s i n (α + β) = \frac{2 a b}{a^{2} + b^{2}}

c o s (α + β) = \frac{b^{2} - a^{2}}{b^{2} + a^{2}}

sin α + sin β = a

cos α + cos β = b

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sin α + sin β = a

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sin α + β = \frac{m a b}{a^{2} + b^{2}}

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