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If θ and ϕ be acute angles and sinθ = 1/2 and cosϕ = 1/3 then: a.π/6 < θ + ϕ...

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madmoni06 | Student | (Level 1) Honors

Posted April 7, 2013 at 9:17 PM via web

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If θ and ϕ be acute angles and sinθ = 1/2 and cosϕ = 1/3 then:

a.π/6 < θ + ϕ < π/3

b.π/3 < θ + ϕ < π/2

c.π/2 < θ + ϕ < 2π/3

d.2π/3 < θ + ϕ < 5π/6

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pramodpandey | College Teacher | (Level 3) Valedictorian

Posted April 8, 2013 at 6:33 AM (Answer #1)

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`sin(theta)=1/2`

`theta=pi/6`

`cos(phi)=1/3`

`pi/4<phi<pi/3`

`pi/6<theta+phi<(pi/3+pi/6)`

`Ans.`

`b`

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