Find tanθ, if secθ = square root of ten divided by three and sinθ < 0.
Solution:
If sec θ = square root of ten divided by three and sin θ < 0
sec θ = (√10)/3 and sin θ < 0
We know that,
cos θ = 1 / sec θ
cos θ = 1/[(√10)/3]
cos θ = (3/√10)
From the trigonometric identity,
sin2θ = 1 - cos2θ
By substituting the value of cos θ,
sin2θ = 1 - (3/√10)2
sin2θ = [1 - (9/10)]
By further calculation,
sin2θ = [(10 - 9) / 10]
sin2θ = 1/10
So we get,
sin θ = +(1/√10), -(1/√10)
sin θ < 0 [Given]
Take the value of sin θ = - (1/√10)
tan θ = (sin θ / cos θ)
tan θ = [ - (1/√10)] / (3/√10)
tanθ = -1/3
Therefore, the value of tan θ is -1/3.
Find tanθ, if secθ = square root of ten divided by three and sinθ < 0.
Summary:
If sec θ = square root of ten divided by three and sin θ < 0, then the value of tan θ is -1/3.
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