sec²(arctan(2)) =
Asqrt(5)
B2
C5 (sec²θ = 1 + tan²θ = 1 + 4 = 5)
D1
Answer & Solution
Correct answer: C. 5 (sec²θ = 1 + tan²θ = 1 + 4 = 5)
Identity: sec²θ = 1 + tan²θ. tan(arctan 2) = 2. So sec²(arctan 2) = 1 + 4 = 5.
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