If sec θ + tan θ = 5, where θ is an acute angle, find the value of sec θ.
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Correct answer: B
Explanation
Given:
secθ + tanθ = 5, θ is an acute angle.
By the formula:
(secθ + tanθ)(secθ − tanθ) = 1
secθ − tanθ = 1/5
secθ + tanθ = 5
secθ − tanθ = 1/5
Add the two:
2secθ = 5 + 1/5 = 26/5
secθ = 13/5