Trigonometric EquationHard
Question
If cos α + cos β = 3/2 and sin α + sin α = 1/2 and θ is the arithmetic mean of α and β, then sin 2θ + cos 2θ is equal to :
Options
A.3/5
B.7/5
C.4/5
D.8/5
Solution
2cos 
and 2 sin
⇒ tan
⇒ sin 2θ + cos2θ = sin (α + β) + cos(α + β)
=
and 2 sin
⇒ tan
⇒ sin 2θ + cos2θ = sin (α + β) + cos(α + β)
=
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