Q8 of 118 Page 5

If sin θ1 + sin θ2 + sin θ3 = 3, then write the value of cos θ1 + cos θ2 + cos θ3.

Given that sin θ1 + sin θ2 + sin θ3 = 3


We know that in general the maximum value of sin θ = 1 when θ = π/2


As sin θ1 + sin θ2 + sin θ3 = 3


⇒ θ1= θ2 = θ3 = π/2.


The above case is the only possible condition for the given condition to satisfy.


∴ cos θ1 + cos θ2 + cos θ3


⇒ cos π/2 + cos π/2 + cos π/2


⇒ 0+0+0


⇒ 0.


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